阅读说明：本技术 带通滤波器 (Band-pass filter ) 是由 泽口修平 芦田裕太 立松雅大 松丸宜纪 户莳重光 于 2021-04-30 设计创作，主要内容包括：本发明提供一种带通滤波器,其具备：不平衡端口；第1平衡端口；第2平衡端口；以及设置于不平衡端口与第1及第2平衡端口之间的第1谐振器、第2谐振器及第3谐振器。第2谐振器和第3谐振器均为两端开放型谐振器,并且在电路结构上相邻且将磁耦合设为主耦合进行电磁耦合。第1谐振器在电路结构上设置于比第3谐振器更接近第2谐振器的位置,并与第3谐振器进行交叉耦合。(The present invention provides a band-pass filter, which comprises: an unbalanced port; 1 st balanced port; a 2 nd balanced port; and a 1 st resonator, a 2 nd resonator, and a 3 rd resonator disposed between the unbalanced port and the 1 st and 2 nd balanced ports. The 2 nd resonator and the 3 rd resonator are both open-ended resonators, and are adjacent to each other in circuit configuration and electromagnetically coupled with the magnetic coupling as a main coupling. The 1 st resonator is provided closer to the 2 nd resonator than the 3 rd resonator in the circuit structure, and cross-coupled with the 3 rd resonator.)

1. A band-pass filter, characterized in that,

the disclosed device is provided with:

an unbalanced port;

1 st balanced port;

a 2 nd balanced port; and

a 1 st resonator, a 2 nd resonator, and a 3 rd resonator disposed between the unbalanced port and the 1 st and 2 nd balanced ports on a circuit structure,

the 2 nd resonator and the 3 rd resonator are both open-ended resonators, and are adjacent in circuit configuration and electromagnetically coupled with magnetic coupling as main coupling,

the 1 st resonator is provided closer to the 2 nd resonator than the 3 rd resonator in a circuit structure, and cross-coupled with the 3 rd resonator.

2. The bandpass filter according to claim 1,

the 1 st resonator is a single-ended short-circuited resonator and is disposed between the unbalanced port and the 2 nd resonator in a circuit configuration.

3. The bandpass filter according to claim 1,

the interval between the 2 nd resonator and the 3 rd resonator is smaller than the interval between the 1 st resonator and the 2 nd resonator.

4. The bandpass filter according to claim 1,

further provided with: a 4 th resonator disposed in circuit configuration between the unbalanced port and the 1 st and 2 nd balanced ports,

the 4 th resonator is provided closer to the 3 rd resonator than the 2 nd resonator in a circuit structure, and cross-coupled with the 2 nd resonator.

5. The bandpass filter according to claim 4,

the 1 st resonator is a single-ended short-circuited resonator and is disposed between the unbalanced port and the 2 nd resonator in a circuit configuration,

the 4 th resonator is a two-end open type resonator, and is disposed between the 1 st balanced port and the 2 nd balanced port and the 3 rd resonator in a circuit configuration.

6. The bandpass filter according to claim 4,

the interval between the 2 nd resonator and the 3 rd resonator is smaller than the interval between the 1 st resonator and the 2 nd resonator and smaller than the interval between the 3 rd resonator and the 4 th resonator.

7. The bandpass filter according to claim 1,

further provided with:

a 1 st capacitor connected to one end of the 2 nd resonator;

a 2 nd capacitor connected to one end of the 3 rd resonator; and

a 3 rd capacitor having a 1 st terminal and a 2 nd terminal,

the 1 st terminal of the 3 rd capacitor is connected to the 1 st capacitor and the 2 nd capacitor,

the 2 nd terminal of the 3 rd capacitor is connected to ground.

8. The bandpass filter according to claim 1,

further provided with: and a laminated body for integrating at least the 2 nd resonator and the 3 rd resonator, the laminated body including a plurality of dielectric layers and a plurality of conductor layers, and a plurality of through holes.

9. The bandpass filter according to claim 8,

the plurality of conductor layers include a plurality of conductor layers for resonators,

the plurality of through holes include a plurality of through holes for resonators,

the 2 nd resonator and the 3 rd resonator respectively include a 1 st via hole row, a 2 nd via hole row, and a conductor layer portion,

wherein the 1 st via hole row and the 2 nd via hole row are each formed by connecting two or more of the plurality of resonator via holes in series and penetrate two or more of the plurality of dielectric layers,

the conductor layer portion is formed by one or more of the plurality of resonator conductor layers, and connects one end of the 1 st via row to one end of the 2 nd via row.

Technical Field

The present invention relates to a balanced bandpass filter including one unbalanced port and a pair of balanced ports.

Background

One of electronic components usable in a transmission/reception circuit of a wireless communication device such as a mobile phone or a wireless LAN communication device is a band pass filter including a plurality of resonators. The band-pass filter preferably has attenuation poles in which the insertion loss changes rapidly in each of a 1 st vicinity region, which is a frequency region lower than the passband and close to the passband, and a 2 nd vicinity region, which is a frequency region higher than the passband and close to the passband.

As the band pass filter, a balanced band pass filter having a pair of balanced ports as output ports is known. The balanced bandpass filter is required to have good amplitude balance characteristics and phase balance characteristics. The good amplitude balance characteristic means that the difference between the amplitudes of the two balance element signals constituting the balance signal output from the band pass filter is close to 0. The good phase balance characteristic means that the phase difference between the two balance element signals is close to 180 degrees.

Japanese patent application laid-open No. 2002-374139 discloses a balanced type LC filter having a pair of balanced input terminals and a pair of balanced output terminals. In the balanced LC filter, an attenuation pole is provided on the lower frequency side or the higher frequency side of the center frequency of the balanced LC filter by a pole adjusting capacitor.

Japanese patent application laid-open No. 2007-267264 discloses a lumped-parameter band-pass filter having a pair of balanced terminals and an unbalanced terminal. Japanese patent application laid-open No. 2007-267264 describes that an unbalanced input-balanced output type filter is configured by using an unbalanced terminal as an input terminal and a pair of balanced terminals as output terminals.

Currently, mobile communication systems up to the 4 th generation are being put into practical use. In addition, currently, standardization of the 5 th generation mobile communication system is progressing. In the conventional balanced bandpass filter, it is difficult to form sharp attenuation poles in the 1 st and 2 nd vicinity regions while satisfying the balance characteristic in these mobile communication systems.

Disclosure of Invention

The present invention has an object to provide a balanced bandpass filter including one unbalanced port and a pair of balanced ports, in which a sharp attenuation pole can be formed while satisfying a balanced characteristic.

The present invention provides a band-pass filter, which comprises: an unbalanced port; 1 st balanced port; a 2 nd balanced port; and a 1 st resonator, a 2 nd resonator, and a 3 rd resonator which are provided between the unbalanced port and the 1 st balanced port and the 2 nd balanced port in a circuit configuration. The 2 nd resonator and the 3 rd resonator are both open-ended resonators, and are adjacent to each other in circuit configuration and electromagnetically coupled with the magnetic coupling as a main coupling. The 1 st resonator is disposed closer to the 2 nd resonator than the 3 rd resonator in the circuit structure, and Cross-coupled (Cross-coupled) with the 3 rd resonator.

In the bandpass filter of the present invention, the following may be used: the 1 st resonator is a single-ended short-circuited resonator and is disposed between the unbalanced port and the 2 nd resonator in a circuit configuration.

In the bandpass filter of the present invention, the following may be used: the interval between the 2 nd resonator and the 3 rd resonator is smaller than that between the 1 st resonator and the 2 nd resonator.

Further, the band pass filter of the present invention may be: further provided with: and a 4 th resonator which is provided between the unbalanced port and the 1 st and 2 nd balanced ports in a circuit configuration. In this case, the following may be used: the 4 th resonator is provided closer to the 3 rd resonator than the 2 nd resonator in the circuit structure, and cross-coupled with the 2 nd resonator. In this case, the following may be used: the 1 st resonator is a single-ended short-circuited resonator and is disposed between the unbalanced port and the 2 nd resonator in a circuit configuration. In addition, it may be: the 4 th resonator is a two-end open type resonator, and is provided between the 1 st balanced port and the 2 nd balanced port and the 3 rd resonator in a circuit configuration.

When the bandpass filter of the present invention includes the 4 th resonator, the following may be used: the interval between the 2 nd resonator and the 3 rd resonator is smaller than the interval between the 1 st resonator and the 2 nd resonator and smaller than the interval between the 3 rd resonator and the 4 th resonator.

Further, the band pass filter of the present invention may be: further provided with: and a laminated body for integrating at least the 2 nd resonator and the 3 rd resonator, the laminated body including a plurality of dielectric layers and a plurality of conductor layers, and a plurality of through holes. In this case, the following may be used: the plurality of conductor layers include a plurality of conductor layers for resonators. It can also be: the plurality of through holes include a plurality of through holes for resonators. In addition, it may be: the 2 nd resonator and the 3 rd resonator respectively include a 1 st via hole row, a 2 nd via hole row, and a conductor layer portion. It can also be: the 1 st via row and the 2 nd via row are each formed by connecting two or more of the plurality of resonator vias in series, and penetrate two or more of the plurality of dielectric layers. It can also be: the conductor layer portion is formed by one or more of the plurality of resonator conductor layers, and connects one end of the 1 st via row to one end of the 2 nd via row.

The band-pass filter of the present invention includes 1 st to 3 rd resonators. The 2 nd resonator and the 3 rd resonator are adjacent to each other in the circuit structure and electromagnetically coupled with the magnetic coupling as a main coupling. The 1 st resonator is provided closer to the 2 nd resonator than the 3 rd resonator in the circuit structure, and cross-coupled with the 3 rd resonator. Thus, according to the present invention, a bandpass filter can be realized that can form a sharp attenuation pole while satisfying the balance characteristic.

Other objects, features and advantages of the present invention will become more fully apparent from the following description.

Drawings

Fig. 1 is a circuit diagram showing a circuit configuration of a bandpass filter according to embodiment 1 of the present invention.

Fig. 2 is a perspective view of the bandpass filter according to embodiment 1 of the present invention.

Fig. 3 is a perspective view of the bandpass filter according to embodiment 1 of the present invention.

Fig. 4 is a perspective view showing the inside of the band pass filter shown in fig. 2 and 3.

Fig. 5A and 5B are explanatory views showing the pattern formation surfaces of the dielectric layers 1 and 2 in the laminated body of the bandpass filter shown in fig. 2 and 3.

Fig. 6A and 6B are explanatory views showing the pattern formation surfaces of the dielectric layers 3 and 4 in the laminated body of the bandpass filter shown in fig. 2 and 3.

Fig. 7A and 7B are explanatory views showing the pattern formation surfaces of the 5 th and 6 th dielectric layers in the laminated body of the bandpass filter shown in fig. 2 and 3.

Fig. 8A and 8B are explanatory views showing the pattern formation surfaces of the 7 th dielectric layer and the 8 th dielectric layer in the laminated body of the bandpass filter shown in fig. 2 and 3.

Fig. 9A is an explanatory view showing a pattern formation surface of the 9 th to 18 th dielectric layers in the laminated body of the bandpass filter shown in fig. 2 and 3.

Fig. 9B is an explanatory diagram showing a pattern formation surface of the 19 th and 20 th dielectric layers in the laminated body of the bandpass filter shown in fig. 2 and 3.

Fig. 10A is an explanatory diagram showing the pattern formation surfaces of the 21 st and 22 nd dielectric layers in the laminated body of the bandpass filter shown in fig. 2 and 3.

Fig. 10B is an explanatory diagram showing a pattern formation surface of the 23 rd dielectric layer in the laminated body of the bandpass filter shown in fig. 2 and 3.

Fig. 11A and 11B are explanatory views showing the pattern formation surfaces of the 24 th and 25 th dielectric layers in the laminated body of the bandpass filter shown in fig. 2 and 3.

Fig. 12 is a characteristic diagram showing the pass characteristic of the 1 st model of the band pass filter.

Fig. 13 is a characteristic diagram showing the pass characteristic of the 2 nd model of the band pass filter.

Fig. 14 is a characteristic diagram showing the pass characteristic of the 3 rd model of the band pass filter.

Fig. 15 is a characteristic diagram showing the pass characteristic of the 4 th model of the band pass filter.

Fig. 16 is a characteristic diagram showing the pass characteristic of the 5 th model of the band pass filter.

Fig. 17 is a characteristic diagram showing an example of the pass characteristic of the bandpass filter according to embodiment 1 of the present invention.

Fig. 18 is a characteristic diagram showing a part of fig. 17 enlarged.

Fig. 19 is a characteristic diagram showing an example of the amplitude balance characteristic of the bandpass filter according to embodiment 1 of the present invention.

Fig. 20 is a characteristic diagram showing an example of the phase balance characteristic of the bandpass filter according to embodiment 1 of the present invention.

Fig. 21 is a characteristic diagram showing an example of reflection characteristics of an unbalanced port of the bandpass filter according to embodiment 1 of the present invention.

Fig. 22 is a characteristic diagram showing an example of reflection characteristics of the 1 st and 2 nd balanced ports of the bandpass filter according to embodiment 1 of the present invention.

Fig. 23 is a circuit diagram showing a circuit configuration of a bandpass filter according to embodiment 2 of the present invention.

Fig. 24 is a perspective view showing the inside of the bandpass filter according to embodiment 2 of the present invention.

Fig. 25A and 25B are explanatory views showing the pattern formation surfaces of the dielectric layers 1 and 2 in the laminated body of the bandpass filter according to embodiment 2 of the invention.

Fig. 26A and 26B are explanatory views showing the pattern formation surfaces of the dielectric layers 3 and 4 in the laminated body of the bandpass filter according to embodiment 2 of the invention.

Fig. 27A and 27B are explanatory views showing the pattern formation surfaces of the 5 th and 6 th dielectric layers in the multilayer body of the bandpass filter according to embodiment 2 of the invention.

Fig. 28A is an explanatory view showing the pattern formation surfaces of the 7 th and 8 th dielectric layers in the laminated body of the bandpass filter according to embodiment 2 of the invention.

Fig. 28B is an explanatory diagram showing a pattern formation surface of the 9 th dielectric layer in the laminated body of the bandpass filter according to embodiment 2 of the invention.

Fig. 29A is an explanatory diagram showing a pattern formation surface of the 10 th dielectric layer in the laminated body of the bandpass filter according to embodiment 2 of the invention.

Fig. 29B is an explanatory view showing the pattern formation surfaces of the dielectric layers of the 11 th to 16 th layers in the laminated body of the bandpass filter according to embodiment 2 of the invention.

Fig. 30A is an explanatory view showing the pattern formation surfaces of the 17 th and 18 th dielectric layers in the laminated body of the bandpass filter according to embodiment 2 of the invention.

Fig. 30B is an explanatory diagram showing the pattern formation surfaces of the 19 th and 20 th dielectric layers in the laminated body of the bandpass filter according to embodiment 2 of the invention.

Fig. 31A and 31B are explanatory views showing the pattern formation surfaces of the 21 st and 22 nd dielectric layers in the multilayer body of the bandpass filter according to embodiment 2 of the invention.

Fig. 32A and 32B are explanatory views showing the pattern formation surfaces of the 23 rd and 24 th dielectric layers in the multilayer body of the bandpass filter according to embodiment 2 of the invention.

Fig. 33 is a characteristic diagram showing an example of the pass characteristic of the bandpass filter according to embodiment 2 of the present invention.

Fig. 34 is a characteristic diagram showing a part of fig. 33 enlarged.

Fig. 35 is a characteristic diagram showing an example of the amplitude balance characteristic of the bandpass filter according to embodiment 2 of the present invention.

Fig. 36 is a characteristic diagram showing an example of the phase balance characteristic of the bandpass filter according to embodiment 2 of the present invention.

Fig. 37 is a characteristic diagram showing an example of reflection characteristics of an unbalanced port of the bandpass filter according to embodiment 2 of the present invention.

Fig. 38 is a characteristic diagram showing an example of reflection characteristics of the 1 st and 2 nd balanced ports of the bandpass filter according to embodiment 2 of the present invention.

Fig. 39 is a circuit diagram showing a circuit configuration of a bandpass filter according to embodiment 3 of the present invention.

Detailed Description

[ embodiment 1 ]

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, a circuit configuration of a bandpass filter according to embodiment 1 of the present invention will be described with reference to fig. 1. Fig. 1 shows a circuit configuration of a bandpass filter according to the present embodiment. As shown in fig. 1, the band-pass filter 1 includes: unbalanced port 11, balanced port 112, balanced port 2 13, resonator 1, resonator 2, resonator 22 3, resonator 23, and resonator 4 24.

The 1 st to 4 th resonators 21 to 24 are provided between the unbalanced port 11 and the 1 st and 2 nd balanced ports 12 and 13 in the circuit configuration. The 2 nd resonator 22 and the 3 rd resonator 23 are adjacent in circuit structure. The 1 st resonator 21 is provided closer to the 2 nd resonator 22 than the 3 rd resonator 23 in terms of circuit configuration. The 4 th resonator 24 is provided in a circuit configuration at a position closer to the 3 rd resonator 23 than the 2 nd resonator 22. In addition, in the present application, the expression "on a circuit configuration" is intended to indicate a configuration on a circuit diagram, not a configuration on a physical configuration.

In the present embodiment, in particular, the 1 st to 4 th resonators 21 to 24 are provided in order from the unbalanced port 11 side. That is, the 2 nd resonator 22 is provided closer to the unbalanced port 11 than the 3 rd resonator 23 in terms of circuit configuration. The 1 st resonator 21 is provided between the unbalanced port 11 and the 2 nd resonator 22 in a circuit configuration. The 4 th resonator 24 is provided between the 1 st and 2 nd balanced ports 12 and 13 and the 3 rd resonator 23 in the circuit configuration.

The 1 st resonator 21 is a single-ended short-circuited resonator. The bandpass filter 1 further includes capacitors C1 and C11. Capacitor C1 connects one end of 1 st resonator 21 to ground. Capacitor C11 connects the one end of 1 st resonator 21 to unbalanced port 11. The other end of the 1 st resonator 21 is connected to the ground.

The 2 nd to 4 th resonators 22 to 24 are all open-ended resonators. The band-pass filter 1 further includes capacitors C2A, C2B, C3A, C3B, C4A, and C4B. The capacitor C2A connects one end of the 2 nd resonator 22 to the ground line. Capacitor C2B connects the other end of 2 nd resonator 22 to ground. The capacitor C3A connects one end of the 3 rd resonator 23 to the ground line. The capacitor C3B connects the other end of the 3 rd resonator 23 to the ground. The capacitor C4A connects one end of the 4 th resonator 24 to the ground. The capacitor C4B connects the other end of the 4 th resonator 24 to ground.

The bandpass filter 1 further includes capacitors C12, C23A, C23B, C34A, and C34B. Capacitor C12 connects the one end of 1 st resonator 21 and the one end of 2 nd resonator 22. Capacitor C23A connects the one end of 2 nd resonator 22 and the one end of 3 rd resonator 23. Capacitor C23B connects the other end of 2 nd resonator 22 and the other end of 3 rd resonator 23. Capacitor C34A connects the one end of 3 rd resonator 23 and the one end of 4 th resonator 24. Capacitor C34B connects the other end of 3 rd resonator 23 and the other end of 4 th resonator 24.

The 1 st balanced port 12 is connected to the one end of the 4 th resonator 24. The 2 nd balanced port 13 is connected to the above-mentioned other end of the 4 th resonator 24.

The 2 nd resonator 22 and the 3 rd resonator 23 are magnetically coupled and capacitively coupled via capacitors C23A, C23B. In fig. 1, the curve marked with the symbol M represents the magnetic coupling between the 2 nd resonator 22 and the 3 rd resonator 23. Here, of the magnetic coupling and the capacitive coupling that contribute to the electromagnetic coupling between the two resonators, the relatively strong coupling is referred to as a primary coupling, and the other coupling is referred to as a secondary coupling. In the present embodiment, in particular, the 2 nd resonator 22 and the 3 rd resonator 23 are electromagnetically coupled by using magnetic coupling as primary coupling and capacitive coupling as secondary coupling.

The 1 st resonator 21 and the 2 nd resonator 22 are magnetically coupled and capacitively coupled via a capacitor C12. In the present embodiment, in particular, the 1 st resonator 21 and the 2 nd resonator 22 are electromagnetically coupled by using capacitive coupling as primary coupling and magnetic coupling as secondary coupling.

The 3 rd resonator 23 and the 4 th resonator 24 are magnetically coupled and capacitively coupled via capacitors C34A, C34B. In the present embodiment, in particular, the 3 rd resonator 23 and the 4 th resonator 24 are electromagnetically coupled by using capacitive coupling as primary coupling and magnetic coupling as secondary coupling.

In addition, the 1 st resonator 21 is magnetically coupled to the 3 rd resonator 23 which is not adjacent to the circuit structure. The 4 th resonator 24 is magnetically coupled to the 2 nd resonator 22 which is not adjacent in the circuit structure. Thus, the electromagnetic coupling between two resonators that are not adjacent in the circuit structure is referred to as cross coupling. In fig. 1, the curve marked with the symbol Mc represents the magnetic coupling between two resonators that are not adjacent on the circuit structure.

Here, the operation of the band-pass filter 1 will be explained. The band-pass filter 1 is a band-pass filter having a predetermined band as a passband. The band-pass filter 1 is a so-called balanced band-pass filter. In the bandpass filter 1, an unbalanced signal is input and output to and from an unbalanced port 11, a 1 st balanced component signal is input and output to and from a 1 st balanced port 12, and a 2 nd balanced component signal is input and output to and from a 2 nd balanced port 13. The 1 st balance element signal and the 2 nd balance element signal constitute a balance signal. The band-pass filter 1 performs conversion between the unbalanced signal and the balanced signal.

Next, the structure of the band-pass filter 1 will be described with reference to fig. 2 to 4. Fig. 2 and 3 are perspective views of the band-pass filter 1. Fig. 4 is a perspective view showing the inside of the band-pass filter 1. The band-pass filter 1 further includes a laminate 30 for integrating the ports 11 to 13, the 1 st to 4 th resonators 21 to 24, and the capacitors C1, C2A, C2B, C3A, C3B, C4A, C4B, C11, C12, C23A, C23B, C34A, and C34B. As will be described in detail later, the laminate 30 includes a plurality of dielectric layers and a plurality of conductor layers, which are laminated, and a plurality of via holes.

The stacked body 30 is formed in a rectangular parallelepiped shape. The laminate 30 has an upper surface 30A, a bottom surface 30B, and four side surfaces 30C to 30F constituting the outer periphery of the laminate 30. Upper surface 30A and bottom surface 30B face opposite sides to each other, side surfaces 30C and 30D also face opposite sides to each other, and side surfaces 30E and 30F also face opposite sides to each other. The side surfaces 30C to 30F are perpendicular to the upper surface 30A and the bottom surface 30B. In the stacked body 30, a direction perpendicular to the upper surface 30A and the bottom surface 30B is a stacking direction of the plurality of dielectric layers and the plurality of conductor layers. In fig. 2 to 4, the stacking direction is indicated by an arrow marked with a symbol T. The upper surface 30A and the bottom surface 30B are located at both ends in the stacking direction T.

Here, as shown in fig. 2 to 4, the X direction, the Y direction, and the Z direction are defined. The X direction, the Y direction and the Z direction are orthogonal to each other. In the present embodiment, one direction parallel to the stacking direction is defined as the Z direction. The direction opposite to the X direction is referred to as the-X direction, the direction opposite to the Y direction is referred to as the-Y direction, and the direction opposite to the Z direction is referred to as the-Z direction.

As shown in fig. 2 and 3, the upper surface 30A is located at the Z-direction end of the laminate 30. The bottom surface 30B is located at the-Z-direction end of the laminated body 30. The side surface 30C is located at the end of the stacked body 30 in the-X direction. The side surface 30D is located at the end of the laminated body 30 in the X direction. The side surface 30E is located at the end of the stacked body 30 in the-Y direction. The side surface 30F is located at the end of the laminated body 30 in the Y direction.

The bandpass filter 1 further includes 1 st to 8 th terminals 111, 112, 113, 114, 115, 116, 117, and 118. The 1 st terminal 111 is disposed from the upper surface 30A to the bottom surface 30B via the side surface 30C. The 2 nd terminal 112 is disposed from the upper surface 30A to the bottom surface 30B via the side surface 30D. The 3 rd to 5 th terminals 113 to 115 are arranged from the upper surface 30A to the bottom surface 30B through the side surface 30E, respectively. The 3 rd to 5 th terminals 113 to 115 are arranged in order in the X direction. The 6 th to 8 th terminals 116 to 118 are arranged from the upper surface 30A to the bottom surface 30B through the side surface 30F. The 6 th to 8 th terminals 116 to 118 are arranged in order in the X direction.

The 1 st terminal 111 corresponds to the unbalanced port 11. The 5 th terminal 115 corresponds to the 2 nd balanced port 13. The 8 th terminal 118 corresponds to the 1 st balanced port 12. The 3 rd, 4 th, 6 th and 7 th terminals 113, 114, 116 and 117 are connected to a ground line, respectively.

Next, the laminated body 30 will be described in detail with reference to fig. 5A to 11B. The stacked body 30 includes 26 dielectric layers stacked. Hereinafter, the 26 dielectric layers are referred to as the 1 st to 26 th dielectric layers in this order from the bottom. The dielectric layers 1 to 26 are denoted by reference numerals 31 to 56.

Fig. 5A shows a pattern formation surface of the 1 st dielectric layer 31. Fig. 5A shows terminal portions 111a to 118a constituting a part of the terminals 111 to 118.

Fig. 5B shows a pattern formation surface of the 2 nd dielectric layer 32. The ground conductor layers 321 and 322 are formed on the pattern formation surface of the dielectric layer 32. The ground conductor layer 321 is connected to the 4 th and 7 th terminals 114 and 117. The ground conductor layer 322 is connected to the 3 rd and 6 th terminals 113 and 116.

Fig. 6A shows a pattern formation surface of the 3 rd dielectric layer 33. On the pattern formation surface of the dielectric layer 33, conductor layers 331, 332, 333, and 334 are formed. The conductor layer 333 is connected to the 8 th terminal 118. The conductor layer 334 is connected to the 5 th terminal 115.

Fig. 6B shows a pattern formation surface of the 4 th dielectric layer 34. On the pattern formation surface of the dielectric layer 34, conductor layers 341, 342, 343, and 344 are formed. In addition, through holes 34T1, 34T2, 34T3, and 34T4 are formed in the dielectric layer 34. The vias 34T1, 34T2, 34T3, and 34T4 are connected to the conductor layers 341, 342, 343, and 344, respectively.

Fig. 7A shows a pattern formation surface of the 5 th dielectric layer 35. A conductive layer 351 is formed on the pattern formation surface of the dielectric layer 35. In addition, the dielectric layer 35 has through holes 35T1, 35T2, 35T3, 35T4, and 35T 5. The vias 35T1, 35T2, 35T3, and 35T4 are connected to vias 34T1, 34T2, 34T3, and 34T4, respectively, formed in the 4 th dielectric layer 34. The via 35T5 is connected to the conductor layer 351.

Fig. 7B shows the patterning surface of the 6 th dielectric layer 36. A conductor layer 361 is formed on the pattern formation surface of the dielectric layer 36. In addition, the dielectric layer 36 is formed with through holes 36T1, 36T2, 36T3, 36T4, 36T5, and 36T 6. The vias 36T1, 36T2, 36T3, 36T4, and 36T5 are connected to vias 35T1, 35T2, 35T3, 35T4, and 35T5, respectively, which are formed in the 5 th dielectric layer 35. The via 36T6 is connected to the conductor layer 361.

Fig. 8A shows a pattern formation surface of the 7 th dielectric layer 37. A conductor layer 371 is formed on the pattern formation surface of the dielectric layer 37. In addition, the dielectric layer 37 has through holes 37T1, 37T2, 37T3, 37T4, 37T5, and 37T 6. The vias 37T1, 37T2, 37T3, 37T4, and 37T6 are connected to vias 36T1, 36T2, 36T3, 36T4, and 36T6, respectively, formed in the 6 th dielectric layer 36. The via 37T5 and the via 36T5 formed in the dielectric layer 36 are connected to the conductor layer 371.

Fig. 8B shows a pattern formation surface of the 8 th dielectric layer 38. A conductor layer 381 is formed on the pattern formation surface of the dielectric layer 38. The conductor layer 381 is connected to the 1 st terminal 111. In addition, the dielectric layer 38 is formed with through holes 38T1, 38T2, 38T3, 38T4, and 38T 5. The vias 38T1, 38T2, 38T3, 38T4, and 38T5 are connected to vias 37T1, 37T2, 37T3, 37T4, and 37T5, respectively, which are formed in the 7 th dielectric layer 37. The via 37T6 formed in the 7 th dielectric layer 37 is connected to the conductor layer 381.

FIG. 9A shows the pattern forming surfaces of the 9 th to 18 th dielectric layers 39 to 48, respectively. Through holes 39T1, 39T2, 39T3, 39T4, and 39T5 are formed in the dielectric layers 39 to 48, respectively. The vias 39T1, 39T2, 39T3, 39T4, and 39T5 formed in the 9 th dielectric layer 39 are connected to the vias 38T1, 38T2, 38T3, 38T4, and 38T5 formed in the 8 th dielectric layer 38, respectively. In the dielectric layers 39 to 49, through holes of the same reference numeral are adjacent to each other in the upper and lower direction.

Fig. 9B shows the pattern formation surfaces of the 19 th and 20 th dielectric layers 49 and 50, respectively. A conductor layer 491 for a resonator is formed on each pattern formation surface of the dielectric layers 49 and 50. The conductor layer 491 for the resonator is connected to the 5 th and 8 th terminals 115 and 118. In addition, through holes 49T1, 49T2, 49T3, 49T4, and 49T5 are formed in the dielectric layers 49 and 50, respectively. The vias 49T1, 49T2, 49T3, 49T4, and 49T5 formed in the 19 th dielectric layer 49 are connected to the vias 39T1, 39T2, 39T3, 39T4, and 39T5 formed in the 18 th dielectric layer 48, respectively. In the dielectric layers 49 and 50, through holes of the same reference numeral are adjacent to each other in the upper and lower direction.

Fig. 10A shows the pattern formation surfaces of the 21 st and 22 nd dielectric layers 51 and 52, respectively. The dielectric layers 51 and 52 have through holes 51T1, 51T2, 51T3, 51T4, and 51T5, respectively. The vias 51T1, 51T2, 51T3, 51T4 and 51T5 formed in the 21 st dielectric layer 51 are connected to the vias 49T1, 49T2, 49T3, 49T4 and 49T5 formed in the 20 th dielectric layer 50, respectively. In the dielectric layers 51 and 52, through holes of the same reference numeral are adjacent to each other in the upper and lower direction.

Fig. 10B shows a pattern formation surface of the 23 rd dielectric layer 53. On the pattern formation surface of the dielectric layer 53, a conductor layer 531 for a resonator is formed. The conductor layer 531 for the resonator is connected to the 3 rd and 6 th terminals 113 and 116. In addition, the dielectric layer 53 is formed with through holes 53T1, 53T2, 53T3, 53T4, and 53T 5. The vias 53T1, 53T2, 53T3, and 53T4 are connected to vias 51T1, 51T2, 51T3, and 51T4, respectively, formed in the 22 nd dielectric layer 52. The via hole 53T5 and the via hole 51T5 formed in the 22 nd dielectric layer 52 are connected to a portion including the center in the longitudinal direction of the conductor layer 531 for resonator, which is a part of the conductor layer 531 for resonator.

Fig. 11A shows a pattern formation surface of the 24 th dielectric layer 54. On the pattern formation surface of the dielectric layer 54, conductor layers 541, 542, and 543 for resonators are formed. The conductor layer 541 for the resonator is connected to the 3 rd and 6 th terminals 113 and 116. The via hole 53T5 formed in the 23 rd dielectric layer 53 is connected to a portion including the center in the longitudinal direction of the conductor layer 541 for a resonator, which is a part of the conductor layer 541 for a resonator. The conductor layers 542 and 543 for the resonator have the 1 st end and the 2 nd end located on opposite sides, respectively.

In addition, the dielectric layer 54 has through holes 54T1, 54T2, 54T3, and 54T 4. The via 54T1 and the via 53T1 formed in the dielectric layer 53 are connected to the portion of the conductor layer 542 for the resonator near the 1 st end. The via 54T2 and the via 53T2 formed in the dielectric layer 53 are connected to the portion of the conductor layer 542 for the resonator near the 2 nd end. The via 54T3 and the via 53T3 formed in the dielectric layer 53 are connected to the portion near the 1 st end of the conductor layer 543 for the resonator. The via 54T4 and the via 53T4 formed in the dielectric layer 53 are connected to the portion near the 2 nd end of the conductor layer 543 for the resonator.

Fig. 11B shows a pattern formation surface of the 25 th dielectric layer 55. On the pattern formation surface of the dielectric layer 55, conductor layers 552 and 553 for a resonator are formed. The conductor layers 552 and 553 for the resonator have the 1 st end and the 2 nd end, respectively, which are located on opposite sides from each other. The via 54T1 formed in the 24 th dielectric layer 54 is connected to the portion near the 1 st end of the conductor layer 552 for the resonator. The via 54T2 formed in the dielectric layer 54 is connected to the portion of the conductor layer 552 for the resonator near the 2 nd end. The via 54T3 formed in the dielectric layer 54 is connected to the vicinity of the 1 st end of the conductor layer 553 for resonator. The via 54T4 formed in the dielectric layer 54 is connected to the portion of the conductor layer 553 for the resonator near the 2 nd end.

Although not shown, marks may be formed on the pattern formation surface of the 26 th dielectric layer 56.

The laminate 30 shown in fig. 2 and 3 is configured by laminating the 1 st to 26 th dielectric layers 31 to 56 so that the pattern formation surface of the 1 st dielectric layer 31 becomes the bottom surface 30B of the laminate 30 and the surface of the 26 th dielectric layer 56 opposite to the pattern formation surface becomes the upper surface 30A of the laminate 30. Then, the 1 st to 8 th terminals 111 to 118 are formed on the outer periphery of the laminate 30, and the bandpass filter 1 shown in fig. 2 and 3 is completed.

The correspondence between the components of the band-pass filter 1 and the components inside the multilayer body 30 shown in fig. 5A to 11B will be described below. The dielectric layers of the multilayer body 30 include the conductor layers 491, 531, 541, 542, 543, 552, and 553 for resonators constituting the 1 st to 4 th resonators 21 to 24. The plurality of through holes of the stacked body 30 include a plurality of resonator through holes for constituting the 1 st to 4 th resonators 21 to 24.

The 1 st resonator 21 is configured by the resonator conductor layers 531, 541, the via holes 35T5, 36T5, 37T5, 38T5, and 53T5, the via holes 39T5 formed in the dielectric layers 39 to 48, the via holes 49T5 formed in the dielectric layers 49 and 50, and the via holes 51T5 formed in the dielectric layers 51 and 52.

The 2 nd resonator 22 is configured by the conductor layers 542 and 552 for the resonator, the vias 34T1, 34T2, 35T1, 35T2, 36T1, 36T2, 37T1, 37T2, 38T1, 38T2, 53T1, 53T2, 54T1, and 54T2, the vias 39T1 and 39T2 formed in the dielectric layers 39 to 48, the vias 49T1 and 49T2 formed in the dielectric layers 49 and 50, and the vias 51T1 and 51T2 formed in the dielectric layers 51 and 52.

As shown in fig. 4, the 2 nd resonator 22 includes a 1 st via hole row 22A, a 2 nd via hole row 22B, and a conductor layer portion 22C. The 1 st via row 22A is configured by connecting in series the vias 34T1, 35T1, 36T1, 37T1, 38T1, 53T1, the vias 39T1 formed in the dielectric layers 39 to 48, the vias 49T1 formed in the dielectric layers 49 and 50, and the vias 51T1 formed in the dielectric layers 51 and 52. The 1 st via row 22A penetrates the dielectric layers 34 to 53.

The 2 nd via column 22B is configured by connecting in series the vias 34T2, 35T2, 36T2, 37T2, 38T2, 53T2, the vias 39T2 formed in the dielectric layers 39 to 48, the vias 49T2 formed in the dielectric layers 49 and 50, and the vias 51T2 formed in the dielectric layers 51 and 52. The 2 nd via hole row 22B penetrates the dielectric layers 34 to 53.

The conductor layer portion 22C is formed by the conductor layers 542 and 552 for the resonator, which are connected to each other by the vias 54T1 and 54T 2. The conductor layer portion 22C connects one end of the 1 st via hole row 22A and one end of the 2 nd via hole row 22B.

The 3 rd resonator 23 is configured by the resonator conductor layers 543 and 553, the vias 34T3, 34T4, 35T3, 35T4, 36T3, 36T4, 37T3, 37T4, 38T3, 38T4, 53T3, 53T4, 54T3, and 54T4, the vias 39T3 and 39T4 formed in the dielectric layers 39 to 48, the vias 49T3 and 49T4 formed in the dielectric layers 49 and 50, and the vias 51T3 and 51T4 formed in the dielectric layers 51 and 52.

As shown in fig. 4, the 3 rd resonator 23 includes a 1 st via hole row 23A, a 2 nd via hole row 23B, and a conductor layer portion 23C. The 1 st via column 23A is configured by connecting in series the vias 34T3, 35T3, 36T3, 37T3, 38T3, 53T3, the vias 39T3 formed in the dielectric layers 39 to 48, the vias 49T3 formed in the dielectric layers 49 and 50, and the vias 51T3 formed in the dielectric layers 51 and 52. The 1 st via hole row 23A penetrates the dielectric layers 34 to 53.

The 2 nd via column 23B is configured by connecting in series the vias 34T4, 35T4, 36T4, 37T4, 38T4, 53T4, the vias 39T4 formed in the dielectric layers 39 to 48, the vias 49T4 formed in the dielectric layers 49 and 50, and the vias 51T4 formed in the dielectric layers 51 and 52. The 2 nd via hole array 23B penetrates the dielectric layers 34 to 53.

The conductor layer portion 23C is formed by the conductor layers 543 and 553 for the resonator, which are connected to each other by the vias 54T3 and 54T 4. Further, the conductor layer portion 23C connects one end of the 1 st via hole row 23A and one end of the 2 nd via hole row 23B.

The 4 th resonator 24 is formed by the resonator conductor layer 491 formed on each of the dielectric layers 49 and 50.

The capacitor C1 is formed by the conductor layers 322 and 351 and the dielectric layers 32 to 34 between the conductor layers 322 and 351.

The capacitor C2A is formed by the conductor layers 321 and 341 and the dielectric layers 32 and 33 between the conductor layers 321 and 341. The capacitor C2B is formed by the conductor layers 321 and 342 and the dielectric layers 32 and 33 between the conductor layers 321 and 342.

The capacitor C3A is formed by the conductor layers 321 and 343 and the dielectric layers 32 and 33 between the conductor layers 321 and 343. The capacitor C3B is formed by the conductor layers 321 and 344 and the dielectric layers 32 and 33 between the conductor layers 321 and 344.

The capacitor C4A is formed by the conductor layers 321 and 333 and the dielectric layer 32 between the conductor layers 321 and 333. The capacitor C4B is formed by the conductor layers 321 and 334 and the dielectric layer 32 between the conductor layers 321 and 334.

Capacitor C11 is formed by conductor layers 351, 361, 371, 381, dielectric layer 35 between conductor layers 351, 361, dielectric layer 36 between conductor layers 361, 371, and dielectric layer 37 between conductor layers 371, 381. The capacitor C12 is formed by the conductor layers 341 and 351 and the dielectric layer 34 between the conductor layers 341 and 351.

The capacitor C23A is formed by the conductor layers 331, 341, 343, and the dielectric layer 33 between the conductor layer 331 and the conductor layers 341, 343. The capacitor C23B is formed by the conductor layers 332, 342, and 344 and the dielectric layer 33 between the conductor layer 332 and the conductor layers 342 and 344.

The capacitor C34A is formed by the conductor layers 333 and 343 and the dielectric layer 33 between the conductor layers 333 and 343. The capacitor C34B is formed by the conductor layers 334 and 344 and the dielectric layer 33 between the conductor layers 334 and 344.

Next, the structural features of the band-pass filter 1 will be described. As shown in fig. 4, the interval between the 2 nd resonator 22 and the 3 rd resonator 23 is smaller than the interval between the 1 st resonator 21 and the 2 nd resonator 22 and smaller than the interval between the 3 rd resonator 23 and the 4 th resonator 24.

As shown in fig. 9B, the resonator conductor layer 491 formed on the dielectric layer 49 and the resonator conductor layer 491 formed on the dielectric layer 50 are arranged so as to overlap each other when viewed from the Z direction. As shown in fig. 10B and 11A, the resonator conductor layer 531 formed on the dielectric layer 53 and the resonator conductor layer 541 formed on the dielectric layer 54 are arranged so as to overlap each other when viewed from the Z direction. As shown in fig. 11A and 11B, the resonator conductor layer 542 formed on the dielectric layer 54 and the resonator conductor layer 552 formed on the dielectric layer 55 are disposed so as to overlap each other when viewed from the Z direction, and the resonator conductor layer 543 formed on the dielectric layer 54 and the resonator conductor layer 553 formed on the dielectric layer 55 are disposed so as to overlap each other when viewed from the Z direction.

As described above, in the bandpass filter 1 of the present embodiment, the 2 nd resonator 22 and the 3 rd resonator 23 are electromagnetically coupled by magnetic coupling as a main coupling, the 1 st resonator 21 and the 3 rd resonator 23 are cross-coupled, and the 4 th resonator 24 and the 2 nd resonator 22 are cross-coupled. According to the present embodiment, these couplings can form attenuation poles in which the insertion loss changes rapidly in each of the 1 st vicinity region, which is a frequency region lower than the passband and closer to the passband, and the 2 nd vicinity region, which is a frequency region higher than the passband and closer to the passband, while satisfying the balance characteristic.

The attenuation pole will be described below with reference to the simulation results. In the simulation, the 1 st to 5 th models of the bandpass filters having the same circuit configuration as that of the bandpass filter 1 of the present embodiment were used. In the simulation, the bandpass filter is designed in such a way that the passband of the bandpass filter includes a frequency band of 3.3 to 3.9 GHz. In the simulation, the pass characteristic of the band pass filter is expressed by using a mixed mode S parameter indicating the response of the difference signal of the 1 st and 2 nd balanced element signals output from the 1 st and 2 nd balanced ports 12 and 13 when the unbalanced signal is input to the unbalanced port 11. Hereinafter, this S parameter is referred to as an insertion loss.

Here, the magnetic coupling coefficient of the 2 nd resonator 22 and the 3 rd resonator 23 is denoted by symbol k23, the magnetic coupling coefficient of the 1 st resonator 21 and the 3 rd resonator 23 in cross coupling is denoted by symbol k13, and the magnetic coupling coefficient of the 2 nd resonator 22 and the 4 th resonator 24 in cross coupling is denoted by symbol k 24. The 1 st to 5 th models are models in which magnetic coupling coefficients k23, k13, and k24 are different from each other. In the simulation, the passage characteristics of each of the 1 st to 5 th models were determined.

First, the passage characteristics of each of the 1 st and 2 nd models will be described. The 1 st model is a model in which the magnetic coupling coefficient k23 is set to 0.37, and the cross-coupled magnetic coupling coefficients k13 and k24 are both set to 0. The model 2 is a model in which the magnetic coupling coefficient k23 is set to 0.07, and the cross-coupled magnetic coupling coefficients k13 and k24 are both set to 0.

Fig. 12 shows the passing characteristics of the 1 st model. Fig. 13 shows the passing characteristics of the 2 nd model. In fig. 12 and 13, the horizontal axis represents frequency and the vertical axis represents insertion loss. As is clear from fig. 12, when the magnetic coupling coefficient k23 is increased and the 2 nd resonator 22 and the 3 rd resonator 23 are electromagnetically coupled by the magnetic coupling as the main coupling, an attenuation pole is formed in a frequency region higher than the passband of the bandpass filter. As is clear from fig. 13, when the magnetic coupling coefficient k23 is reduced and the 2 nd resonator 22 and the 3 rd resonator 23 are electromagnetically coupled by capacitive coupling as the main coupling, an attenuation pole is formed in a frequency region lower than the passband of the bandpass filter.

In general, in a bandpass filter including two resonators, it is known that when a magnetic coupling coefficient between the two resonators is relatively large and a coupling capacity between the two resonators is relatively small, an attenuation pole is formed in a frequency region higher than a center frequency of a passband of the bandpass filter. In the 1 st and 2 nd models, the magnetic coupling coefficients k13 and k24 of the cross coupling are set to 0 in order to clarify the change of the attenuation pole due to the difference in electromagnetic coupling between the 2 nd resonator 22 and the 3 rd resonator 23. However, the above description of the change of the attenuation pole is also applicable to the case where the magnetic coupling coefficients k13 and k24 have values other than 0. In the present embodiment, as described above, the 2 nd resonator 22 and the 3 rd resonator 23 are electromagnetically coupled by the magnetic coupling as the main coupling, thereby forming the attenuation pole in the 2 nd vicinity region.

Next, the passing characteristics of the 3 rd model will be described. The 3 rd model is a model in which the magnetic coupling coefficient k23 is 0.37, the cross-coupled magnetic coupling coefficient k13 is 0.032, and the cross-coupled magnetic coupling coefficient k24 is 0.

Fig. 14 shows the passing characteristics of the 3 rd model. In fig. 14, the horizontal axis represents frequency and the vertical axis represents insertion loss. As is clear from the passing characteristics of the 1 st model (both the magnetic coupling coefficients k13 and k24 of the cross coupling are 0) shown in fig. 14 and 12, the attenuation pole is formed in the frequency region lower than the passband of the bandpass filter by the cross coupling of the 1 st resonator 21 and the 3 rd resonator 23. In the present embodiment, as described above, the 3 rd resonator 23 and the 1 st resonator 21 are cross-coupled to form an attenuation pole in the 1 st vicinity.

Next, the passing characteristics of the 4 th model will be described. The 4 th model is a model in which the magnetic coupling coefficient k23 is 0.37, the cross-coupled magnetic coupling coefficient k13 is 0, and the cross-coupled magnetic coupling coefficient k24 is 0.02.

Fig. 15 shows the passing characteristics of the 4 th model. In fig. 15, the horizontal axis represents frequency and the vertical axis represents insertion loss. As is clear from the passing characteristics of the 1 st model (both the magnetic coupling coefficients k13 and k24 of the cross coupling are 0) shown in fig. 15 and 12, the attenuation pole is formed in the frequency region lower than the passband of the bandpass filter by the cross coupling of the 2 nd resonator 22 and the 4 th resonator 24. In the present embodiment, as described above, the 4 th resonator 24 and the 2 nd resonator 22 are cross-coupled to form an attenuation pole in the 1 st vicinity.

Next, the passing characteristics of the 5 th model will be described. The 5 th model is a model in which the magnetic coupling coefficient k23 is 0.37, the cross-coupled magnetic coupling coefficient k13 is 0.032, and the cross-coupled magnetic coupling coefficient k24 is 0.02.

Fig. 16 shows the passing characteristics of the 5 th model. In fig. 16, the horizontal axis represents frequency and the vertical axis represents insertion loss. From the pass characteristic of the 3 rd model (the magnetic coupling coefficient k24 is 0) shown in fig. 16 and 14 and the pass characteristic of the 4 th model (the magnetic coupling coefficient k13 is 0) shown in fig. 15, the attenuation pole formed by two cross couplings is sharper than the attenuation pole formed by one cross coupling shown in fig. 14 and 15. This is caused by the coincidence of the effect of one cross-coupling with the effect of the other cross-coupling. In the present embodiment, the attenuation pole formed in the 1 st vicinity is made sharper by the two cross couplings.

As can be understood from the results of the simulations shown in fig. 12 to 16, according to the present embodiment, by setting the main coupling between the 2 nd resonator 22 and the 3 rd resonator 23 to magnetic coupling, sharp attenuation poles can be formed in the 1 st and 2 nd vicinity regions by at least one of the cross coupling between the 1 st resonator 21 and the 3 rd resonator 23 and the cross coupling between the 2 nd resonator 22 and the 4 th resonator 24. In addition, according to the present embodiment, the attenuation pole formed in the 1 st vicinity can be made sharper by utilizing both the cross coupling of the 1 st resonator 21 with the 3 rd resonator 23 and the cross coupling of the 2 nd resonator 22 with the 4 th resonator 24.

However, in the present embodiment, the interval between the 2 nd resonator 22 and the 3 rd resonator 23 is smaller than the interval between the 1 st resonator 21 and the 2 nd resonator 22 and smaller than the interval between the 3 rd resonator 23 and the 4 th resonator 24. In the present embodiment, in particular, the capacitive coupling between the 2 nd resonator 22 and the 3 rd resonator 23 is strong while the distance between the 2 nd resonator 22 and the 3 rd resonator 23 is small and the magnetic coupling between the 2 nd resonator 22 and the 3 rd resonator 23 is strong. Thereby, the frequency of the attenuation pole formed in the 2 nd vicinity region becomes a frequency close to the passband. Thus, according to the present embodiment, a characteristic in which the insertion loss rapidly changes in the vicinity of the passband can be realized. In addition, an example in which the distance between the 2 nd resonator 22 and the 3 rd resonator 23 is increased as compared with the present embodiment will be described in embodiment 2.

In addition, according to the present embodiment, the attenuation pole can be formed as described above while satisfying the balance characteristic. This effect will be described below with reference to an example of the characteristics of the band-pass filter 1.

In the present embodiment, each of the 2 nd to 4 th resonators 22 to 24 is a resonator having both open ends. In the two-end open type resonator, a circuit configuration symmetrical about the resonator can be provided. In the present embodiment, as shown in fig. 1, the circuit configuration is symmetrical about the 2 nd to 4 th resonators 22 to 24, and the group of capacitors C2A, C3A, C4A, C23A, and C34A and the group of capacitors C2B, C3B, C4B, C23B, and C34B are paired.

Here, both ends of the resonator having both ends open are referred to as a 1 st end and a 2 nd end. In the two-end open type resonator, when the balance between the 1 st end side and the 2 nd end side of the electric field and the magnetic field is broken, the balance characteristic is deteriorated. In the present embodiment, by providing the 4 th resonator 24, the circuit configuration of the bandpass filter 1 is made more symmetrical than the case where the 4 th resonator 24 is not provided. Thus, according to the present embodiment, the unbalance of the electric field and the magnetic field can be further alleviated, and the balance characteristics can be further improved.

Next, an example of the characteristics of the band-pass filter 1 according to the present embodiment will be described with reference to fig. 17 to 22. Here, an example of the characteristics of the band pass filter 1 when the band pass filter 1 is designed so that the passband thereof includes a band of 3.3GHz to 3.9GHz is shown.

Fig. 17 shows an example of the pass characteristic of the band-pass filter 1. Fig. 18 is an enlarged view of a part of fig. 17. Here, the insertion loss is expressed as a pass characteristic of the band pass filter 1. In fig. 17 and 18, the horizontal axis represents frequency and the vertical axis represents insertion loss. As shown in fig. 17, in the bandpass filter 1, attenuation poles whose insertion loss changes sharply are formed in the 1 st and 2 nd vicinity regions, respectively.

The insertion loss is preferably 2.5dB or less. As shown in fig. 18, in the band-pass filter 1, the insertion loss is 2.5dB or less in the above-mentioned frequency band.

Fig. 19 shows an example of the amplitude balance characteristic of the band-pass filter 1. Here, the amplitude balance characteristic of the band pass filter 1 is represented by the difference in the amplitudes of the 1 st and 2 nd balance element signals (hereinafter referred to as amplitude difference) output from the 1 st and 2 nd balance ports 12 and 13 when an unbalanced signal is input to the unbalanced port 11. The amplitude difference is expressed by a positive value when the amplitude of the 1 st balance element signal is larger than the amplitude of the 2 nd balance element signal, and by a negative value when the amplitude of the 1 st balance element signal is smaller than the amplitude of the 2 nd balance element signal. In fig. 19, the horizontal axis represents frequency, and the vertical axis represents amplitude difference. When the amplitude difference is expressed as m (dB), the value of m is preferably-1.5 or more and 1.5 or less, more preferably-1.0 or more and 1.0 or less. As shown in fig. 19, in the band-pass filter 1, the value of m is a value of-1.0 to 1.0 in the above-mentioned frequency band.

Fig. 20 shows an example of the phase balance characteristic of the band-pass filter 1. Here, the phase balance characteristic of the band pass filter 1 is expressed by using a difference in phase (hereinafter, referred to as a phase difference) between the 1 st and 2 nd balance element signals output from the 1 st and 2 nd balance ports 12 and 13 when an unbalanced signal is input to the unbalanced port 11. The phase difference indicates a magnitude of phase progression of the 1 st balance element signal with respect to the 2 nd balance element signal. In fig. 20, the horizontal axis represents frequency and the vertical axis represents phase difference. When the phase difference is represented by p (deg), the value of p is preferably 165 or more and 195 or less. As shown in fig. 20, in the band-pass filter 1, the value of p is 165 to 195 inclusive in the above-described frequency band.

Fig. 21 shows an example of the reflection characteristic of the unbalanced port 11 of the band pass filter 1. Fig. 22 shows an example of the reflection characteristics of the 1 st and 2 nd balanced ports 12 and 13 of the band-pass filter 1. In fig. 21 and 22, the horizontal axis represents frequency and the vertical axis represents reflection loss. The reflection loss is preferably 10dB or more. As shown in fig. 21 and 22, in the bandpass filter 1, the reflection loss is 10dB or more in the above-described frequency band.

As described above, the band-pass filter 1 having the characteristics shown in fig. 17 to 22 can be used at least in the frequency band of 3.3GHz to 3.9GHz, and has a well-balanced characteristic in this frequency band. As can be understood from fig. 17 to 22, according to the bandpass filter 1, sharp attenuation poles can be formed in the 1 st and 2 nd vicinity regions while satisfying the balance characteristic.

[ 2 nd embodiment ]

Next, embodiment 2 of the present invention will be explained. First, the circuit configuration of the bandpass filter according to the present embodiment will be briefly described with reference to fig. 23. Fig. 23 shows a circuit configuration of the bandpass filter according to the present embodiment.

The circuit configuration of the band-pass filter 101 of the present embodiment is different from the band-pass filter 1 of embodiment 1 in the following points. In the present embodiment, the capacitor C23B that connects the end on the capacitor C2B side of the 2 nd resonator 22 and the end on the capacitor C3B side of the 3 rd resonator 23 is not provided. The other circuit configuration of the band-pass filter 101 is the same as that of the band-pass filter 1 of embodiment 1.

Next, the structure of the band-pass filter 101 will be described. Fig. 24 is a perspective view showing the inside of the band-pass filter 101. The band pass filter 101 includes a multilayer body 30 and 1 st to 8 th terminals 111 to 118 (see fig. 2 and 3) as in the band pass filter 1 of embodiment 1. The multilayer body 30 in the present embodiment is a multilayer body for integrating the ports 11 to 13, the 1 st to 4 th resonators 21 to 24, and the capacitors C1, C2A, C2B, C3A, C3B, C4A, C4B, C11, C12, C23A, C34A, and C34B. The shape and arrangement of the 1 st to 8 th terminals 111 to 118 are the same as those of embodiment 1.

Next, the laminate 30 of the present embodiment will be described in detail with reference to fig. 25A to 32B. In the present embodiment, the stacked body 30 includes 25 stacked dielectric layers instead of the dielectric layers 31 to 56 of embodiment 1. Hereinafter, the 25 dielectric layers are referred to as the 1 st to 25 th dielectric layers in this order from the bottom. The dielectric layers 1 to 25 are denoted by reference numerals 61 to 85.

Fig. 25A shows a pattern formation surface of the 1 st dielectric layer 61. Fig. 25A shows terminal portions 111a to 118a constituting parts of terminals 111 to 118, respectively.

Fig. 25B shows a pattern formation surface of the 2 nd dielectric layer 62. A ground conductor layer 621 is formed on the patterned surface of the dielectric layer 62. The ground conductor layer 621 is connected to the 4 th and 7 th terminals 114 and 117.

Fig. 26A shows a pattern formation surface of the 3 rd dielectric layer 63. A conductor layer 631 is formed on the pattern formation surface of the dielectric layer 63. In addition, a via 63T5 is formed in the dielectric layer 63. The via 63T5 is connected to the conductor layer 631.

Fig. 26B shows a pattern formation surface of the 4 th dielectric layer 64. On the pattern formation surface of the dielectric layer 64, conductor layers 641, 642, 643 are formed. The conductor layer 641 is connected to a via 63T5 formed in the 3 rd dielectric layer 63. The conductor layer 632 is connected to the 8 th terminal 118. The conductor layer 633 is connected to the 5 th terminal 115.

Fig. 27A shows a pattern formation surface of the 5 th dielectric layer 65. On the pattern formation surface of the dielectric layer 65, conductor layers 651, 652, 653, and 654 are formed. In addition, the dielectric layer 65 is formed with through holes 65T1, 65T2, 65T3, and 65T 4. The via holes 65T1, 65T2, 65T3, and 65T4 are connected to the conductor layers 651, 652, 653, and 654, respectively.

Fig. 27B shows a pattern formation surface of the 6 th dielectric layer 66. A conductive layer 661 is formed on the patterned surface of the dielectric layer 66. In addition, the dielectric layer 66 is formed with through holes 66T1, 66T2, 66T3, 66T4, and 66T 5. The vias 66T1, 66T2, 66T3, and 66T4 are connected to vias 65T1, 65T2, 65T3, and 65T4, respectively, formed in the 5 th dielectric layer 65. The via 66T5 is connected to the conductor layer 661.

Fig. 28A shows the pattern formation surfaces of the 7 th and 8 th dielectric layers 67 and 68, respectively. The dielectric layers 67 and 68 are formed with vias 67T1, 67T2, 67T3, 67T4, and 67T5, respectively. The vias 67T1, 67T2, 67T3, 67T4, and 67T5 formed in the 7 th dielectric layer 67 are connected to the vias 66T1, 66T2, 66T3, 66T4, and 66T5 formed in the 6 th dielectric layer 66, respectively. In the dielectric layers 67 and 68, through holes of the same reference numeral adjacent to each other vertically are connected to each other.

Fig. 28B shows a pattern formation surface of the 9 th dielectric layer 69. A conductor layer 691 is formed on the pattern formation surface of the dielectric layer 69. The conductor layer 691 is connected to the 1 st terminal 111. In addition, the dielectric layer 69 has through holes 69T1, 69T2, 69T3, 69T4, and 69T 5. The vias 69T1, 69T2, 69T3, 69T4, and 69T5 are connected to vias 67T1, 67T2, 67T3, 67T4, and 67T5, respectively, formed in the 8 th dielectric layer 68.

Fig. 29A shows a pattern formation surface of the 10 th dielectric layer 70. A conductor layer 701 is formed on the pattern formation surface of the dielectric layer 70. In addition, the dielectric layer 70 is formed with through holes 70T1, 70T2, 70T3, 70T4, and 70T 5. The vias 70T1, 70T2, 70T3, and 70T4 are connected to vias 69T1, 69T2, 69T3, and 69T4, respectively, formed in the 9 th dielectric layer 69. The via 70T5 and the via 69T5 formed in the 9 th dielectric layer 69 are connected to the conductor layer 701.

FIG. 29B shows the pattern forming surfaces of the 11 th to 16 th dielectric layers 71 to 76. Through holes 71T1, 71T2, 71T3, 71T4 and 71T5 are formed in the dielectric layers 71 to 76, respectively. Vias 70T1, 70T2, 70T3, 70T4, and 70T5 formed in the 10 th dielectric layer 70 are connected to the vias 71T1, 71T2, 71T3, 71T4, and 71T5 formed in the 11 th dielectric layer 71, respectively. In the dielectric layers 71 to 76, through holes of the same reference numeral are adjacent to each other in the upper and lower direction.

Fig. 30A shows a pattern formation surface of the 17 th and 18 th dielectric layers 77 and 78. A conductor layer 771 for resonator is formed on the patterned surface of each of the dielectric layers 77 and 78. The conductor layer 771 for resonator is connected to the 5 th and 8 th terminals 115 and 118. In addition, through holes 77T1, 77T2, 77T3, 77T4, and 77T5 are formed in the dielectric layers 77 and 78, respectively. The via holes 77T1, 77T2, 77T3, 77T4, and 77T5 formed in the 17 th dielectric layer 77 are connected to the via holes 71T1, 71T2, 71T3, 71T4, and 71T5 formed in the 16 th dielectric layer 76, respectively. In the dielectric layers 77 and 78, through holes of the same reference numeral adjacent to each other vertically are connected to each other.

Fig. 30B shows the pattern formation surfaces of the 19 th and 20 th dielectric layers 79 and 80, respectively. In addition, through holes 79T1, 79T2, 79T3, 79T4, and 79T5 are formed in the dielectric layers 79 and 80, respectively. The through holes 79T1, 79T2, 79T3, 79T4, and 79T5 formed in the 19 th dielectric layer 79 are connected to the through holes 77T1, 77T2, 77T3, 77T4, and 77T5 formed in the 18 th dielectric layer 78, respectively. In the dielectric layers 79 and 80, through holes of the same reference numeral adjacent to each other vertically are connected to each other.

Fig. 31A shows a pattern formation surface of the 21 st dielectric layer 81. A conductor layer 811 for a resonator is formed on the pattern formation surface of the dielectric layer 81. The conductor layer 811 for the resonator is connected to the 3 rd and 6 th terminals 113 and 116. In addition, through holes 81T1, 81T2, 81T3, 81T4, and 81T5 are formed in the dielectric layer 81. Through holes 79T1, 79T2, 79T3, and 79T4 formed in the 20 th dielectric layer 80 are connected to the through holes 81T1, 81T2, 81T3, and 81T4, respectively. The via hole 81T5 and the via hole 79T5 formed in the 20 th dielectric layer 80 are connected to a portion including the center in the longitudinal direction of the conductor layer 811 for a resonator, which is a part of the conductor layer 811 for a resonator.

Fig. 31B shows a pattern formation surface of the 22 nd dielectric layer 82. A conductor layer 821 for a resonator is formed on the pattern formation surface of the dielectric layer 82. The conductor layer 821 for the resonator is connected to the 3 rd and 6 th terminals 113 and 116. The via hole 81T5 formed in the 21 st dielectric layer 81 is connected to a portion including the center in the longitudinal direction of the resonator conductor layer 821 which is a part of the resonator conductor layer 821. In addition, the dielectric layer 82 is formed with through holes 82T1, 82T2, 82T3, 82T4, and 82T 5. Through holes 81T1, 81T2, 81T3, and 81T4 formed in the dielectric layer 81 are connected to the through holes 82T1, 82T2, 82T3, and 82T4, respectively.

Fig. 32A shows a pattern formation surface of the 23 rd dielectric layer 83. On the patterned surface of the dielectric layer 83, the conductor layers 832 and 833 for the resonator are formed. The conductor layers 832 and 833 for the resonator have the 1 st end and the 2 nd end located on the opposite sides, respectively. In addition, through holes 83T1, 83T2, 83T3, and 83T4 are formed in the dielectric layer 83. The via 83T1 and the via 82T1 formed in the 22 nd dielectric layer 82 are connected to the vicinity of the 1 st end of the conductor layer 832 for the resonator. The via 83T2 and the via 82T2 formed in the dielectric layer 82 are connected to the portion near the 2 nd end of the conductor layer 832 for the resonator. The via 83T3 and the via 82T3 formed in the dielectric layer 82 are connected to the vicinity of the 1 st end of the conductor layer 833 for the resonator. The via 83T4 and the via 82T4 formed in the dielectric layer 82 are connected to the vicinity of the 2 nd end of the conductor layer 833 for the resonator.

Fig. 32B shows a pattern formation surface of the 24 th dielectric layer 84. On the patterned surface of the dielectric layer 84, the conductor layers 842, 843 for the resonator are formed. The resonator conductor layers 842, 843 have the 1 st end and the 2 nd end located on opposite sides, respectively. The via 83T1 formed in the 23 rd dielectric layer 83 is connected to a portion near the 1 st end of the conductor layer 842 for a resonator. The via 83T2 formed in the dielectric layer 83 is connected to a portion near the 2 nd end of the conductor layer 842 for the resonator. The via hole 83T3 formed in the dielectric layer 83 is connected to the vicinity of the 1 st end of the conductor layer 843 for the resonator. The via hole 83T4 formed in the dielectric layer 83 is connected to the vicinity of the 2 nd end of the conductor layer 843 for the resonator.

Although not shown, marks may be formed on the pattern formation surface of the 25 th dielectric layer 85.

The laminate 30 of the present embodiment is configured by laminating the 1 st to 25 th dielectric layers 61 to 85 so that the pattern formation surface of the 1 st dielectric layer 61 becomes the bottom surface 30B (see fig. 2 and 3) of the laminate 30 and the surface of the 25 th dielectric layer 85 opposite to the pattern formation surface becomes the upper surface 30A (see fig. 2 and 3) of the laminate 30. Then, the 1 st to 8 th terminals 111 to 118 are formed on the outer periphery of the laminated body 30, and the band pass filter 101 is completed.

The correspondence between the components of the band-pass filter 101 and the internal components of the multilayer body 30 shown in fig. 25A to 32B will be described below. In the present embodiment, the dielectric layers of the stacked body 30 include the conductor layers 771, 811, 821, 832, 833, 842, and 843 for the resonators 1 to 4 to constitute the resonators 21 to 24.

The 1 st resonator 21 is configured by the resonator conductor layers 811 and 821, the via holes 70T5 and 81T5, the via hole 71T5 formed in the dielectric layers 71 to 76, the via hole 77T5 formed in the dielectric layers 77 and 78, and the via hole 79T5 formed in the dielectric layers 79 and 80.

The 2 nd resonator 22 is configured by the resonator conductor layers 832 and 842, the through holes 65T1, 65T2, 66T1, 66T2, 69T1, 69T2, 70T1, 70T2, 81T1, 81T2, 82T1, 82T2, 83T1, and 83T2, the through holes 67T1 and 67T2 formed in the dielectric layers 67 and 68, the through holes 71T1 and 71T2 formed in the dielectric layers 71 to 76, the through holes 77T1 and 77T2 formed in the dielectric layers 77 and 78, and the through holes 79T1 and 79T2 formed in the dielectric layers 79 and 80.

The 2 nd resonator 22 includes a 1 st via hole row 22A, a 2 nd via hole row 22B, and a conductor layer portion 22C (see fig. 24), as in embodiment 1. The 1 st via row 22A is configured by connecting in series via holes 65T1, 66T1, 69T1, 70T1, 81T1, 82T1, via holes 67T1 formed in the dielectric layers 67 and 68, via holes 71T1 formed in the dielectric layers 71 to 76, via holes 77T1 formed in the dielectric layers 77 and 78, and via holes 79T1 formed in the dielectric layers 79 and 80. The 1 st via row 22A penetrates the dielectric layers 65 to 82.

The 2 nd via row 22B is configured by connecting in series the vias 65T2, 66T2, 69T2, 70T2, 81T2, 82T2, the vias 67T2 formed in the dielectric layers 67 and 68, the vias 71T2 formed in the dielectric layers 71 to 76, the vias 77T2 formed in the dielectric layers 77 and 78, and the vias 79T2 formed in the dielectric layers 79 and 80. The 2 nd via hole row 22B penetrates the dielectric layers 65 to 82.

The conductor layer portion 22C is formed by the conductor layers 832 and 842 for the resonator, which are connected to each other by the through holes 83T1 and 83T 2.

The 3 rd resonator 23 is configured by the resonator conductor layers 833, 843, the via holes 65T3, 65T4, 66T3, 66T4, 69T3, 69T4, 70T3, 70T4, 81T3, 81T4, 82T3, 82T4, 83T3, and 83T4, the via holes 67T3 and 67T4 formed in the dielectric layers 67 and 68, the via holes 71T3 and 71T4 formed in the dielectric layers 71 to 76, the via holes 77T3 and 77T4 formed in the dielectric layers 77 and 78, and the via holes 79T3 and 79T4 formed in the dielectric layers 79 and 80.

The 3 rd resonator 23 includes a 1 st via hole row 23A, a 2 nd via hole row 23B, and a conductor layer portion 23C (see fig. 24), as in embodiment 1. The 1 st via row 23A is configured by connecting in series via holes 65T3, 66T3, 69T3, 70T3, 81T3, 82T3, via holes 67T3 formed in the dielectric layers 67 and 68, via holes 71T3 formed in the dielectric layers 71 to 76, via holes 77T3 formed in the dielectric layers 77 and 78, and via holes 79T3 formed in the dielectric layers 79 and 80. The 1 st via row 23A penetrates the dielectric layers 65 to 82.

The 2 nd via column 23B is configured by connecting in series via holes 65T4, 66T4, 69T4, 70T4, 81T4, 82T4, via holes 67T4 formed in the dielectric layers 67 and 68, via holes 71T4 formed in the dielectric layers 71 to 76, via holes 77T4 formed in the dielectric layers 77 and 78, and via holes 79T4 formed in the dielectric layers 79 and 80. The 2 nd via row 23B penetrates the dielectric layers 65 to 82.

The conductor layer portion 23C is formed by the conductor layers 833 and 843 for the resonator, which are connected to each other by the via holes 83T3 and 83T 4.

The 4 th resonator 24 is formed by the resonator conductor layer 771 formed on each of the dielectric layers 77 and 78.

Capacitor C1 is formed by dielectric layers 62 to 69 between conductor layers 621 and 701 and conductor layers 621 and 701.

Capacitor C2A is formed by dielectric layers 62 to 64 between conductor layers 621 and 651 and conductor layers 621 and 651. Capacitor C2B is formed by dielectric layers 62 to 64 between conductor layers 621 and 652 and conductor layers 621 and 652.

The capacitor C3A is formed by dielectric layers 62 to 64 between the conductor layers 621 and 653 and the conductor layers 621 and 653. Capacitor C3B is formed by dielectric layers 62 to 64 between conductor layers 621 and 654 and conductor layers 621 and 654.

Capacitor C4A is formed by dielectric layers 62 and 63 between conductor layers 621 and 642 and conductor layers 621 and 642. Capacitor C4B is formed by dielectric layers 62 and 63 between conductor layers 621 and 643 and conductor layers 621 and 643.

Capacitor C11 is formed by dielectric layer 69 between conductor layers 691, 701 and conductor layers 691, 701. The capacitor C12 is formed by the conductor layers 651 and 661 and the dielectric layer 65 between the conductor layers 651 and 661.

Capacitor C23A is formed by conductor layers 631, 641, 651, 653, dielectric layers 63, 64 between conductor layers 631, 653, dielectric layer 63 between conductor layers 631, 641, and dielectric layer 64 between conductor layers 641, 651.

Capacitor C34A is formed by dielectric layer 64 between conductor layers 642 and 653 and conductor layers 642 and 653. The capacitor C34B is formed by the dielectric layer 64 between the conductor layers 643 and 654 and the conductor layers 643 and 654.

Next, the structural features of the band-pass filter 101 will be described with reference to fig. 24. In the present embodiment, the interval between the 2 nd resonator 22 and the 3 rd resonator 23 is smaller than the interval between the 1 st resonator 21 and the 2 nd resonator 22 and smaller than the interval between the 3 rd resonator 23 and the 4 th resonator 24. In the present embodiment, the distance between the 2 nd resonator 22 and the 3 rd resonator 23 is larger than the distance between the 2 nd resonator 22 and the 3 rd resonator 23 in embodiment 1 (see fig. 4).

As shown in fig. 30A, the resonator conductor layer 771 formed on the dielectric layer 77 and the resonator conductor layer 771 formed on the dielectric layer 78 are arranged so as to overlap each other when viewed from the Z direction. As shown in fig. 31A and 31B, the conductor layer 811 formed on the dielectric layer 81 and the conductor layer 821 formed on the dielectric layer 82 are arranged so as to overlap each other when viewed from the Z direction. As shown in fig. 32A and 32B, the resonator conductor layer 832 formed on the dielectric layer 83 and the resonator conductor layer 842 formed on the dielectric layer 84 are disposed so as to overlap each other when viewed from the Z direction, and the resonator conductor layer 833 formed on the dielectric layer 83 and the resonator conductor layer 843 formed on the dielectric layer 84 are disposed so as to overlap each other when viewed from the Z direction.

Next, the operation and effect of the band-pass filter 101 of the present embodiment will be described. In the present embodiment, as in embodiment 1, attenuation poles whose insertion loss changes rapidly are formed in the 1 st vicinity region, which is a frequency region lower than the passband and close to the passband, and in the 2 nd vicinity region, which is a frequency region higher than the passband and close to the passband.

In this embodiment, in particular, the capacitive coupling between the 2 nd resonator 22 and the 3 rd resonator 23 is reduced compared to the 1 st embodiment while the distance between the 2 nd resonator 22 and the 3 rd resonator 23 is increased compared to the 1 st embodiment and the magnetic coupling between the 2 nd resonator 22 and the 3 rd resonator 23 is reduced compared to the 1 st embodiment. Specifically, the capacitive coupling between the 2 nd resonator 22 and the 3 rd resonator 23 is reduced by not providing the capacitor C23B. The capacitive coupling of the 2 nd resonator 22 and the 3 rd resonator 23 is adjusted by the capacitor C23A. On the other hand, in embodiment 1, the capacitive coupling between the 2 nd resonator 22 and the 3 rd resonator 23 is adjusted by the capacitors C23A and C23B. According to the present embodiment, the adjustment of the capacitive coupling between the 2 nd resonator 22 and the 3 rd resonator 23 is easier than that of embodiment 1.

Next, an example of the characteristics of the band-pass filter 101 according to the present embodiment will be described with reference to fig. 33 to 38. Here, an example of the characteristics of the band pass filter 101 when the band pass filter 101 is designed so that the passband thereof includes a band of 4.7GHz to 5.1GHz is shown.

Fig. 33 shows an example of the pass characteristic of the band-pass filter 101. Fig. 34 is an enlarged view of a part of fig. 33. Here, the insertion loss when an unbalanced signal is input to the unbalanced port 11 is shown as the pass characteristic of the band pass filter 101. In fig. 33 and 34, the horizontal axis represents frequency and the vertical axis represents insertion loss. As shown in fig. 33, in the band-pass filter 101, attenuation poles whose insertion loss changes rapidly are formed in the 1 st vicinity region, which is a frequency region lower than the passband and close to the passband, and in the 2 nd vicinity region, which is a frequency region higher than the passband and close to the passband.

As is clear from a comparison between fig. 33 and fig. 17 showing an example of the pass characteristics of the band-pass filter 1 according to embodiment 1, the following differences are present. In the band-pass filter 101, the attenuation pole formed in the frequency region on the high frequency side is farther from the passband than the band-pass filter 1. This is caused by the fact that while the distance between the 2 nd resonator 22 and the 3 rd resonator 23 in the band pass filter 101 is increased as compared with the band pass filter 1, the magnetic coupling of the 2 nd resonator 22 and the 3 rd resonator 23 is weakened as compared with the band pass filter 1, and the capacitive coupling of the 2 nd resonator 22 and the 3 rd resonator 23 by the capacitors C23A, C23B is also weakened as compared with the band pass filter 1. In other words, according to fig. 17 and 33, the frequency of the attenuation pole formed in the 2 nd vicinity can be brought close to the passband by increasing the capacitive coupling between the 2 nd resonator 22 and the 3 rd resonator 23 while reducing the interval between the 2 nd resonator 22 and the 3 rd resonator 23 and increasing the magnetic coupling between the 2 nd resonator 22 and the 3 rd resonator 23.

The insertion loss is preferably 3.0dB or less. As shown in fig. 34, the band-pass filter 101 has an insertion loss of 3.0dB or less in the above-mentioned frequency band.

Fig. 35 shows an example of the amplitude balance characteristic of the band-pass filter 101. Here, as in fig. 19 of embodiment 1, the amplitude balance characteristic of the band-pass filter 101 is shown by using the amplitude difference. In fig. 35, the horizontal axis represents frequency, and the vertical axis represents amplitude difference. When the amplitude difference is expressed as m (dB), the value of m is preferably-1.5 or more and 1.5 or less, more preferably-1.0 or more and 1.0 or less. As shown in fig. 35, in the band-pass filter 101, the value of m is a value of-1.0 to 1.0 in the above-mentioned frequency band.

Fig. 36 shows an example of the phase balance characteristic of the band-pass filter 101. Here, as in fig. 20 of embodiment 1, the phase balance characteristic of the band pass filter 101 is shown using a phase difference. In fig. 36, the horizontal axis represents frequency and the vertical axis represents phase difference. When the phase difference is represented by p (deg), the value of p is preferably 165 or more and 195 or less. As shown in fig. 35, in the band-pass filter 101, the value of p is 165 to 195 inclusive in the above-described frequency band.

Fig. 37 shows an example of the reflection characteristic of the unbalanced port 11 of the band pass filter 101. Fig. 38 shows an example of the reflection characteristics of the 1 st and 2 nd balanced ports 12 and 13 of the band pass filter 101. In fig. 37 and 38, the horizontal axis represents frequency and the vertical axis represents reflection loss. The reflection loss is preferably 10dB or more. As shown in fig. 37 and 38, in the band-pass filter 101, the reflection loss is 10dB or more in the above-described frequency band.

As described above, the band-pass filter 101 having the characteristics shown in fig. 33 to 38 can be used at least in the band of 4.7GHz to 5.1GHz, and has a well-balanced characteristic in this band. As can be understood from fig. 33 to 38, according to the bandpass filter 101, sharp attenuation poles can be formed in the 1 st and 2 nd vicinity regions while satisfying the balance characteristic.

Other structures, operations, and effects of the present embodiment are the same as those of embodiment 1.

[ embodiment 3 ]

Next, embodiment 3 of the present invention will be explained. First, a circuit configuration of the band pass filter according to the present embodiment will be described with reference to fig. 39. Fig. 39 shows a circuit configuration of the bandpass filter according to the present embodiment.

The circuit configuration of the band-pass filter 201 of the present embodiment is different from the band-pass filter 101 of embodiment 2 in the following points. In the present embodiment, the capacitor C23A that connects the end on the capacitor C2A side of the 2 nd resonator 22 and the end on the capacitor C3A side of the 3 rd resonator 23 is not provided.

The band-pass filter 201 includes capacitors C5A and C5B. The capacitors C5A, C5B have terminals 1 and 2, respectively. The 1 st terminal of the capacitor C5A is connected to the capacitors C2A, C3A. The 2 nd terminal of the capacitor C5A is connected to ground.

The 1 st terminal of the capacitor C5B is connected to the capacitors C2B, C3B. The 2 nd terminal of the capacitor C5B is connected to ground.

The other circuit configuration of the band-pass filter 201 is the same as that of the band-pass filter 101 according to embodiment 2.

In the present embodiment, the group of capacitors C2A, C3A, and C5A and the group of capacitors C2B, C3B, and C5B are all connected by a so-called Y-connection. Thus, according to the present embodiment, the capacitances of the capacitors C2A, C2B, C3A, C3B, C5A, and C5B can be reduced as compared with the case where the groups are connected by so-called pi connection or delta connection. As a result, according to the present embodiment, the band pass filter 201 can be downsized.

Other structures, operations, and effects of the present embodiment are the same as those of embodiment 2.

The present invention is not limited to the above embodiments, and various modifications can be made. For example, the bandpass filter of the present invention may be integrated with other circuits to form a single laminated electronic component. Examples of the other circuits include a demultiplexer circuit, a filter, and an integrator circuit.

As is apparent from the above description, various embodiments and modifications of the present invention can be implemented. Therefore, the present invention can be implemented in a form other than the above-described preferred form within the scope and equivalence of the claims.