阅读说明：本技术 双频谐振器及使用该双频谐振器的双频带通滤波器 (Dual-frequency resonator and dual-frequency band-pass filter using same ) 是由 关谷尚人 海野雄丈 鹤冈勉 岸田和人 佐藤庸夫 北田典敬 于 2018-04-27 设计创作，主要内容包括：本发明提供相比现有技术能够进一步小型化的双频谐振器。双频谐振器(10)具备第一导体部(20)和第二导体部(30),第一导体部(20)在中央部的第一折返部(21)折返并以预定间隔邻接地沿预定方向延伸,比第一折返部(21)靠一端(28)侧的导体部分(26)和比第一折返部(21)靠另一端(29)侧的导体部分(27)还成为在一端(28)及另一端(29)与第一折返部(21)之间的第二折返部(22)向一端(28)及另一端(29)相互分离的方向折返的构造,第二导体部(30)与第一导体部(20)的第一折返部(21)连续地沿预定方向延伸,第一导体部(20)构成半波长谐振器,在第一导体部(20)产生奇模谐振,第一导体部(20)及第二导体部(30)构成半波长谐振器,在第一导体部(20)及第二导体部(30)产生偶模谐振。(The invention provides a dual-frequency resonator which can be further miniaturized compared with the prior art. A dual-band resonator (10) is provided with a first conductor part (20) and a second conductor part (30), wherein the first conductor part (20) is folded at a first folded part (21) in the center part and extends in a predetermined direction in an adjacent manner at a predetermined interval, a conductor part (26) closer to one end (28) than the first folded part (21) and a conductor part (27) closer to the other end (29) than the first folded part (21) are further folded at a second folded part (22) between the one end (28) and the other end (29) and the first folded part (21) in a direction in which the one end (28) and the other end (29) are separated from each other, the second conductor part (30) extends continuously in the predetermined direction with the first folded part (21) of the first conductor part (20), the first conductor part (20) constitutes a half-wave resonator, odd-mode resonance occurs in the first conductor part (20), and the first conductor part (20) and the second conductor part (30) constitute a half-wave resonator, an even-mode resonance is generated in the first conductor part (20) and the second conductor part (30).)

1. A dual-frequency resonator resonating at two different frequencies,

Comprises a first conductor part and a second conductor part formed on or in a dielectric having a ground conductor,

The first conductor part is folded back in a U-shape at a first folding part at a central part and extends in a predetermined direction in an adjacent manner at a predetermined interval,

One end side conductor portion of the first conductor portion on one end side of the first folded portion and the other end side conductor portion of the first conductor portion on the other end side of the first folded portion have the following configurations: a second turn-back portion between one end and the other end and the first turn-back portion, turning back in a direction in which the one end and the other end are separated from each other,

The one end of the second conductor portion is connected to the first folded portion of the first conductor portion and extends continuously in the predetermined direction with respect to the first conductor portion,

Wherein both ends of the first conductor section are open, the first conductor section forms a half-wavelength resonator, and odd-mode resonance that resonates at one of the two frequencies is generated in the first conductor section,

The other end of the second conductor portion is open, the first conductor portion and the second conductor portion constitute a half-wavelength resonator, and an even-mode resonance that resonates at the other of the two frequencies is generated in the first conductor portion and the second conductor portion.

2. The dual-frequency resonator according to claim 1,

The one end side conductor portion and the other end side conductor portion further have the following configurations: and third folded portions between the one end and the other end and the first folded portion and the second folded portion are folded in a direction in which the second folded portions are separated from each other.

3. The dual-frequency resonator according to claim 2,

The first folded portion, the one end, and the second folded portion are arranged in this order in a direction intersecting the predetermined direction in the one-end-side conductor portion,

In the other-end side conductor portion, the first folded portion, the other end, and the second folded portion are arranged in this order in the intersecting direction.

4. The dual-frequency resonator according to claim 3,

The first folded portion, the one end, and the second folded portion are arranged linearly in the intersecting direction in the one-end-side conductor portion,

In the other-end side conductor portion, the first folded portion, the other end, and the second folded portion are arranged linearly in the intersecting direction.

5. The dual-frequency resonator according to any one of claims 1 to 4,

The first conductor portion is made thinner than the second conductor portion, and the second conductor portion has a stepped impedance structure.

6. The dual-frequency resonator according to any one of claims 1 to 5,

A concave portion or a convex portion is formed at an end portion of the second conductor portion on the other end side.

7. A dual-band bandpass filter is characterized in that,

A dual-band resonator comprising one or more of the dual-band resonators defined in any one of claims 1-6.

8. The dual-band bandpass filter according to claim 7, characterized by comprising:

A plurality of dual-frequency resonators arranged in such a manner as to satisfy a coupling coefficient of odd-mode resonance; and

And one or more waveguides provided between the second conductor portions of the plurality of dual-band resonators so as to satisfy a coupling coefficient of even-mode resonance.

9. The dual-band bandpass filter of claim 8,

The double-frequency resonator further includes a pair of feed lines provided so as to sandwich the plurality of double-frequency resonators and coupled to the first conductor portion and the second conductor portion of the double-frequency resonator, respectively.

Technical Field

The present invention relates to a dual-band resonator that resonates at two different frequencies and a dual-band bandpass filter using the dual-band resonator.

Background

In recent years, the use of wireless communication terminals such as smartphones and tablet computers has increased, and the use of large-capacity contents such as videos has increased, and data traffic has increased at a rate of 1.5 times the annual rate, and is expected to continue to increase in the future.

Therefore, in order to realize high speed and large capacity of the network, Carrier Aggregation (CA) technology for performing communication by simultaneously using a plurality of frequency bands has been introduced by each communication carrier. In the CA technology, a multi-band bandpass filter that passes signals of a plurality of frequency bands simultaneously is required.

Patent documents 1 and 2 disclose a dual band bandpass filter that passes signals of two frequency bands simultaneously. The dual-band resonator constituting the dual-band bandpass filter simultaneously realizes two frequency bands using two modes generated in one resonator. Specifically, the dual-frequency resonator has the following configuration: a strip conductor is formed on the upper surface of a dielectric body having a ground conductor disposed on the lower surface thereof, and a stub conductor (stub, second conductor portion) is added to a half-wavelength resonator (first conductor portion). In the dual-band resonator, odd mode resonance occurs in the half-wavelength resonator, and even mode resonance occurs in the half-wavelength resonator and the conductor stub. By sharing one resonator in two frequency bands in this way, the dual-band resonator and the dual-band bandpass filter can be downsized compared to using two independent resonators.

Disclosure of Invention

Problems to be solved by the invention

The invention aims to provide a dual-frequency resonator which can be more miniaturized than the prior art and a dual-frequency band-pass filter using the dual-frequency resonator.

Means for solving the problems

(1) A dual-band resonator according to the present invention is a dual-band resonator resonating at two different frequencies, including a first conductor section and a second conductor section formed on or in a dielectric having a ground conductor, the first conductor section being folded back in a U-shape at a first folded-back section in a central portion thereof and extending in a predetermined direction while being adjacent to each other at a predetermined interval, one end side conductor portion of the first conductor section on one end side of the first folded-back section and the other end side conductor portion of the first conductor section on the other end side of the first folded-back section further having: a second folded portion between one end and the other end and the first folded portion, the second folded portion being folded back in a direction in which the one end and the other end are separated from each other, the one end of the second conductor portion being connected to the first folded portion of the first conductor portion and continuously extending in the predetermined direction with respect to the first conductor portion, both ends of the first conductor portion being open, the first conductor portion constituting a half-wave resonator, the first conductor portion generating an odd-mode resonance that resonates at one of the two frequencies, the second conductor portion having the other end open, the first conductor portion and the second conductor portion constituting a half-wave resonator, and the first conductor portion and the second conductor portion generating an even-mode resonance that resonates at the other of the two frequencies.

(2) In the dual-band resonator described in (1), the one-end-side conductor portion and the other-end-side conductor portion may have the following structures: and third folded portions between the one end and the other end and the first folded portion and the second folded portion are folded in a direction in which the second folded portions are separated from each other.

(3) In the dual-band resonator described in (2), the first folded portion, the one end, and the second folded portion may be arranged in the one-end-side conductor portion in the order of a cross direction intersecting the predetermined direction, and the first folded portion, the other end, and the second folded portion may be arranged in the other-end-side conductor portion in the order of the cross direction.

(4) In the dual-band resonator described in (3), the first folded portion, the one end, and the second folded portion may be arranged linearly in the intersecting direction in the one-end-side conductor portion, and the first folded portion, the other end, and the second folded portion may be arranged linearly in the intersecting direction in the other-end-side conductor portion.

(5) In the dual-band resonator according to any one of (1) to (4), the first conductor portion may be made thinner than the second conductor portion, and the second conductor portion may have a stepped impedance structure.

(6) The dual-band resonator according to any one of (1) to (5), wherein a concave portion or a convex portion is formed at an end portion of the second conductor portion on the other end side.

(7) A dual-band bandpass filter according to the present invention includes one or more dual-band resonators according to any one of (1) to (6).

(8) The dual band bandpass filter according to (7) may further include: a plurality of dual-frequency resonators arranged in such a manner as to satisfy a coupling coefficient of odd-mode resonance; and one or more waveguides provided between the second conductor portions of the plurality of dual-band resonators in such a manner as to satisfy a coupling coefficient of even-mode resonance.

(9) The dual-band bandpass filter according to (8) may further include a pair of feed lines provided so as to sandwich the plurality of dual-band resonators and coupled to the first conductor portion and the second conductor portion of the dual-band resonators, respectively.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a dual-band resonator that can be further miniaturized than the conventional one and a dual-band bandpass filter using the dual-band resonator can be provided.

Drawings

Fig. 1 is a side view of a conventional dual-band resonator.

fig. 2 is a top view of a conventional dual-frequency resonator.

Fig. 3A is a schematic diagram of current distribution of odd mode resonance of a conventional dual-frequency resonator.

Fig. 3B is a schematic diagram of current distribution of even mode resonance of the conventional dual-frequency resonator.

fig. 4A is a simulation result of current distribution of odd mode resonance of the conventional dual-frequency resonator.

Fig. 4B is a simulation result of current distribution of even mode resonance of the conventional dual frequency resonator.

Fig. 5 is a plan view of a conventional dual-band bandpass filter.

Fig. 6 is a plan view of a conventional dual band bandpass filter.

Fig. 7A is a simulation result of the S parameter (S21 (pass characteristic)) in the design of the conventional example of fig. 6.

Fig. 7B is an enlarged view showing S21 (pass characteristic) and S11 (reflection characteristic) in an enlarged manner in a VIIB portion (near the odd-mode resonance frequency) of fig. 7A.

Fig. 7C is an enlarged view showing S21 (pass characteristic) and S11 (reflection characteristic) in an enlarged manner in a VIIC portion (near the even-mode resonance frequency) of fig. 7A.

Fig. 8A shows the result of actual measurement of the S parameter (S21 (passing characteristic)) in the conventional example of fig. 6.

Fig. 8B is an enlarged view showing S21 (pass characteristic) and S11 (reflection characteristic) in an enlarged manner in a portion VIIIB (near the odd-mode resonance frequency) of fig. 8A.

Fig. 8C is an enlarged view showing S21 (pass characteristic) and S11 (reflection characteristic) in an enlarged manner in a viic portion (near the even-mode resonance frequency) of fig. 8A.

Fig. 9A is a plan view of the dual-band resonator of the present embodiment.

fig. 9B is a plan view of another dual-band resonator according to this embodiment.

Fig. 10A is a schematic diagram of the current distribution of the even mode resonance of the dual-frequency resonator of the present embodiment.

Fig. 10B is a schematic diagram of the current distribution of the even mode resonance of the other dual-frequency resonator of the present embodiment.

Fig. 11 is a plan view of the dual band bandpass filter of the present embodiment.

Fig. 12 is a plan view of a dual-band resonator according to a modification of the present embodiment.

Fig. 13 is a plan view of a dual band bandpass filter according to a modification of the present embodiment.

Fig. 14 is a top view of the dual band bandpass filter of the present embodiment.

Fig. 15A is a simulation result of the S parameter (S21 (pass characteristic)) at the time of design of the embodiment of fig. 14.

Fig. 15B is an enlarged view showing S21 (pass characteristic) and S11 (reflection characteristic) in the XVB portion (near the odd-mode resonance frequency) of fig. 15A in an enlarged manner.

Fig. 15C is an enlarged view showing S21 (pass characteristic) and S11 (reflection characteristic) of the XVC portion (near the even-mode resonance frequency) of fig. 15A in an enlarged manner.

Fig. 16A is the result of actual measurement of the S parameter (S21 (pass characteristic)) in the example of fig. 14.

Fig. 16B is an enlarged view showing S21 (pass characteristic) and S11 (reflection characteristic) in the XVIB portion (near the odd-mode resonance frequency) of fig. 16A in an enlarged manner.

fig. 16C is an enlarged view showing S21 (pass characteristic) and S11 (reflection characteristic) in the XVIC portion (near the even-mode resonance frequency) of fig. 16A in an enlarged manner.

Detailed Description

Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals.

First, prior to the description of the present embodiment, a conventional dual-band resonator and a dual-band bandpass filter, which are studied by the inventors of the present application, will be described.

(existing Dual-frequency resonator)

Fig. 1 is a side view of a conventional dual-frequency resonator, and fig. 2 is a top view of the conventional dual-frequency resonator. Fig. 1 and 2 show XYZ rectangular coordinate systems. The X direction (cross direction) is a width direction of a filter described below, the Y direction (predetermined direction) is a length direction of the filter, and the Z direction is a height direction of the filter.

As shown in fig. 1, a conventional dual-band resonator 10X is formed of a conductor having a microstrip line structure formed on a dielectric 11. A ground conductor 12 is formed on the back surface of the dielectric 11. The dual-band resonator 10X may be formed of a conductor having a strip line structure formed inside a dielectric, or may be formed of a conductor having a coplanar line or a grounded coplanar line structure formed on a dielectric.

as the dielectric 11, a known dielectric can be used. For example, a material having excellent formability can be used as the material of the dielectric 11. As the material of the dielectric 11, a material having a small dielectric loss tangent may be used in order to reduce the dielectric loss. As the material of the dielectric 11, a material having a high thermal conductivity may be used in order to reduce a temperature rise.

As the conductor constituting the dual-band resonator 10X and the ground conductor 12, a known conductor can be used. For example, as the conductor, a normal conductor can be used. In addition, as the conductor, a superconductor may be used in order to reduce conductor loss.

As shown in fig. 2, the dual-band resonator 10X includes a first conductor 20X and a second conductor 30X.

The first conductor portion 20X has a so-called hairpin shape. Specifically, the first conductor portion 20X has a structure in which a first folded portion 21 at the center of a linear conductor is folded in a U shape. The conductor portion 26 on the one end 28 side of the first folded portion 21 and the conductor portion 27 on the other end 29 side of the first folded portion 21 extend in the Y direction while being adjacent to each other at a predetermined interval. Both ends 28, 29 of the first conductor 20X are open, and the first conductor 20X constitutes a U-shaped half-wavelength resonator.

The second conductor portion 30X has a so-called stub (stub) shape. Specifically, one end 38 of the second conductor portion 30X is connected to the first turn portion 21 of the first conductor portion 20X, and extends continuously in the Y direction from the first conductor portion 20X. The second conductor portion 30X has the other end 39 opened, and the second conductor portion 30X and the first conductor portion 20X constitute a linear (I-shaped) half-wavelength resonator extending from the one end 28 and the other end 29 of the first conductor portion 20X toward the other end 39 of the second conductor portion 30X.

In the dual-band resonator 10X configured as described above, the AB plane extending in the Y direction through the center in the X direction is formed as an electromagnetic wall, and odd mode resonance occurs in the U-shaped half-wavelength resonator configured by the first conductor portion 20X, and even mode resonance occurs in the linear (I-shaped) half-wavelength resonator configured by the first conductor portion 20X and the second conductor portion 30X. Thereby, the dual-band resonator 10X resonates at two frequencies (bands) of the odd mode resonance frequency and the even mode resonance frequency.

Fig. 3A is a schematic diagram of a current distribution of an odd mode resonance of the conventional dual-frequency resonator 10X, and fig. 3B is a schematic diagram of a current distribution of an even mode resonance of the conventional dual-frequency resonator 10X. Fig. 4A is a simulation result of current distribution of odd mode resonance of the conventional dual-band resonator 10X, and fig. 4B is a simulation result of current distribution of even mode resonance of the conventional dual-band resonator 10X. The simulations of fig. 4A and 4B use an electromagnetic field analysis simulator SONNET EM (manufactured by SONNET research). Arrows in fig. 3A and 3B, and fig. 4A and 4B show the direction of the current.

Since the one end 28 and the other end 29 of the first conductor portion 20X are open ends (in other words, the first conductor portion 20X is a half-wavelength resonator) and the first folded portion 21 is the central portion of the first conductor portion 20X, the current of the odd mode resonance is the largest and the voltage is 0V in the first folded portion 21 as shown in fig. 3A. Thus, in the odd-mode resonance, the boundary surface 40 between the first conductor portion 20X and the second conductor portion 30X can be regarded as GND, and the influence of the second conductor portion 30X can be ignored. Therefore, the resonance frequency of the odd mode is determined by the entire length of the U-shaped first conductor part 20.

According to the simulation result of fig. 4A, the current at the odd mode resonance flows in the first conductor portion 20X and does not flow in the second conductor portion 30X. From this, it is understood that the second conductor portion 30X does not affect the odd-mode resonance. The portion where the current is the largest is the first turn portion 21 of the first conductor portion 20X. Therefore, it is understood that the first conductor portion 20X operates as a half-wavelength resonator at the odd-mode resonance.

on the other hand, since the one end 28 and the other end 29 of the first conductor portion 20X and the other end 39 of the second conductor portion 30X are open ends (in other words, the first conductor portion 20X and the second conductor portion 30X are linear half-wavelength resonators), the current of the even mode resonance is the maximum and the voltage is 0V at the center portions of the first conductor portion 20X and the second conductor portion 30X as shown in fig. 3B. Therefore, the resonance frequency of the even mode is determined mainly by the length from the one end 28 and the other end 29 of the first conductor portion 20X to the other end 39 of the second conductor portion 30X.

As a result of the simulation shown in fig. 4B, the current at the time of the even mode resonance is concentrated on the left and right side surfaces of the first conductor portion 20X and the second conductor portion 30X without flowing into the electric/magnetic wall of the AB surface. The portion where the current is the largest is the center portion in the Y direction of the first conductor portion 20X and the second conductor portion 30X. Therefore, it is known that the first conductor portion 20X and the second conductor portion 30X operate as linear half-wavelength resonators at the time of even mode resonance.

Referring again to fig. 2, in the dual-band resonator 10X, the length L1 of the first conductor portion 20X is changed without changing the length L2 of the first conductor portion 20X and the second conductor portion 30X (in this case, the length of the second conductor portion 30X is also changed), whereby the resonance frequency of the odd mode can be adjusted without affecting the resonance frequency of the even mode. In the dual-band resonator 10X, the length L2 of the first conductor portion 20X and the second conductor portion 30X (that is, the length of the second conductor portion 30X) is changed without changing the length L1 of the first conductor portion 20X, whereby the resonance frequency of the even mode can be adjusted without affecting the resonance frequency of the odd mode. Thereby, the dual-band resonator 10X can adjust the two resonance frequencies, respectively.

(existing double-frequency band-pass filter)

Fig. 5 is a plan view of a conventional dual-band bandpass filter. The dual-band bandpass filter 1X shown in fig. 5 is constituted by a conductor having a microstrip line structure formed on the dielectric 11, similarly to the configuration shown in fig. 1. The dual band bandpass filter 1X includes power feed lines 51X and 52X, two of the dual band resonators 10X described above, and a waveguide 60X.

The feeder lines 51X and 52X are conductors for inputting and outputting signals, and are arranged so as to sandwich the dual-band resonator 10X in the X direction.

The dual-band resonator 10X is arranged in the X direction between the power supply lines 51X and 52X. The dual-band resonators 10X are arranged in directions different from each other by 180 degrees. In other words, the adjacent dual band resonators 10X are arranged in directions different from each other by 180 degrees.

The waveguide 60X is an H-shaped conductor and is disposed between the dual-band resonators 10X. The waveguide 60X is disposed in the center of the dual-band resonator 10X in the Y direction.

According to the dual band pass filter 1X, the coupling coefficient of the even mode can be adjusted without affecting the coupling coefficient of the odd mode by changing the distance d between the dual band resonators 10X. On the other hand, by changing the length l of the waveguide 60X, the coupling coefficient of the odd mode can be adjusted without affecting the coupling coefficient of the even mode. This is for the following reason.

since the U-shaped first conductor portions 20X are close to each other and the directions of currents of the odd mode resonances are opposite to each other, magnetic fields radiated to the outside cancel each other and become small in the odd mode resonances. Therefore, the odd-mode coupling between the adjacent dual-band resonators 10X becomes small. As a result, the dependence of the odd-mode coupling coefficient on the distance d between the dual-band resonators 10X is reduced.

On the other hand, the waveguide 60X is disposed in the center portion in the X direction, that is, in a portion where the current of the even mode resonance is large and the voltage is small, in other words, in a portion where the magnetic field coupling of the even mode is large. In general, the closer the conductors, the more dominant the electric field coupling, and the more separated the conductors, the more dominant the magnetic field coupling. Since electric field coupling dominates in waveguide 60X, it is substantially not coupled to the even mode resonator. As a result, the coupling coefficient of the even mode becomes less dependent on the length l of the waveguide 60X.

In summary, according to the dual-band bandpass filter 1X of the comparative example, the coupling coefficient of the odd mode and the coupling coefficient of the even mode can be adjusted separately.

(evaluation results of conventional example)

The dual-band bandpass filter 1X of the conventional example was designed and manufactured, and evaluated.

Fig. 6 is a plan view of the dual band bandpass filter 1X of the conventional example designed and manufactured in this evaluation. As shown in fig. 6, the dual-band bandpass filter 1X of the conventional example designed and manufactured in this evaluation includes 7 layers of dual-band resonators 10X.

In the dual-band resonator 10X, the dual-band resonator 10X shown in fig. 2 and 5 has a stepped impedance structure. Specifically, the vicinity of one end 28 and the other end 29 of the conductor portions 26 and 27 of the first conductor portion 20X is thinned, and the vicinity of the first folded portion 21 is thickened. This adjusts the frequency of the even mode resonance and the frequency of the odd mode resonance.

Further, a protrusion 45X is provided at the center portion in the Y direction of the first conductor portion 20X and the second conductor portion 30X. In the center portion of the first conductor portion 20X and the second conductor portion 30X in the Y direction, the current of the even mode resonance is the maximum, and the voltage is 0V, so that the frequency of the even mode resonance is not affected by the protrusion portion 45X. This adjusts the frequency of the odd-mode resonance.

A waveguide 70X is also provided. The waveguide 70X is disposed in the vicinity of the second conductor portion 30X so as to extend in the X direction between the dual-band resonators 10X. This makes a fine adjustment of the coupling coefficient of the even mode.

As shown in fig. 6, the distance d between the dual-band resonators 10X is adjusted in each layer.

The design conditions and design parameters are as follows.

Resonant frequency of odd mode 1.5GHz

Frequency bandwidth of odd mode 22.5MHz

Fluctuation of odd mode 0.03dB

Resonance frequency of even mode 2.0GHz

Frequency bandwidth of even mode 30.0MHz

Even mode fluctuation of 0.03dB

Fig. 7A to 7C show simulation results of the S parameter at the time of design. Fig. 7A shows S21 (pass characteristic) of the conventional example of fig. 6, fig. 7B shows S21 (pass characteristic) and S11 (reflection characteristic) of VIIB portion (near the odd mode resonance frequency) of fig. 7A in an enlarged manner, and fig. 7C shows S21 (pass characteristic) and S11 (reflection characteristic) of VIIC portion (near the even mode resonance frequency) of fig. 7A in an enlarged manner. The simulations of fig. 7A to 7C use an electromagnetic field analysis simulator SONNET EM (manufactured by SONNET research).

Fig. 8A to 8C show actual measurement results of the S parameter of the manufactured conventional example. Fig. 8A shows S21 (pass characteristic) of the conventional example of fig. 6, fig. 8B shows S21 (pass characteristic) and S11 (reflection characteristic) of VIIIB portion (near the odd mode resonance frequency) of fig. 8A in an enlarged manner, and fig. 8C shows S21 (pass characteristic) and S11 (reflection characteristic) of VIIIC portion (near the even mode resonance frequency) of fig. 8A in an enlarged manner. In the measurement of fig. 8A to 8C, a network analyzer E5063A (manufactured by deluxe corporation) was used.

From fig. 7A to 7C and fig. 8A to 8C, measurement results substantially the same as the simulation results were obtained, and the effectiveness of the method of the conventional example was confirmed.

The size of the dual-band resonator 10X of the conventional example of fig. 6 is 2.6mm (X direction) × 28.7mm (Y direction), and the size of the dual-band bandpass filter 1X of the conventional example of fig. 6 is 50.0mm (X direction) × 39.1mm (Y direction). In this way, the dual-band resonator 10X and the dual-band bandpass filter 1X of the conventional example can realize two frequency bands at the same time by using two modes generated in one resonator, thereby enabling downsizing compared to the case of using two independent resonators.

Here, in the conventional dual-band resonator 10X, the magnetic field radiated to the outside is large in the even mode resonance, and the coupling between the adjacent resonators is large when the filter is configured. Therefore, in order to obtain desired coupling in the even mode resonance, the distance between the resonators becomes large, and the size of the entire filter becomes large.

Therefore, the present embodiment provides a dual-band resonator and a dual-band bandpass filter that can be further miniaturized than the conventional one.

(Dual-band resonator of the present embodiment)

Fig. 9A is a plan view of the dual-band resonator of the present embodiment. The dual-band resonator 10 shown in fig. 9A is composed of a conductor having a microstrip line structure formed on a dielectric, as in the conventional dual-band resonator 10X shown in fig. 1.

As shown in fig. 9A, the dual-band resonator 10 includes a first conductor section 20 and a second conductor section 30.

The first conductor portion 20 has a structure in which a first turn portion 21 at the center of a linear conductor is turned in a U shape, similarly to the conventional first conductor portion 20X shown in fig. 2. The conductor portion 26 of the first conductor portion 20 on the one end 28 side of the first folded portion 21 and the conductor portion 27 of the first conductor portion 20 on the other end 29 side of the first folded portion 21 extend in the Y direction while being adjacent to each other at a predetermined interval.

The conductor portions 26 and 27 are folded outward at the second folded portion 22 at the center between the first folded portion 21 and the one and other ends 28 and 29. That is, the conductor portion 26 and the conductor portion 27 are folded back in the direction in which the one end 28 and the other end 29 are separated from each other at the second folded portion 22.

In other words, the conductor portion 26 is configured to be folded back in the direction of separation from the conductor portion 27 in the X direction at the second folded-back portion 22, and the conductor portion 27 is configured to be folded back in the direction of separation from the conductor portion 26 in the X direction at the second folded-back portion 22.

In the present embodiment, the conductor portion 26 and the conductor portion 27 are folded back so that one end 28 and the other end 29 are adjacent to the first folded portion 21. This makes it possible to independently adjust the coupling coefficient of the even mode by the waveguide 60 in fig. 11 described below, and to obtain the effect that the magnetic fields radiated to the outside in the even mode resonance cancel each other and become small to the maximum.

The conductor portion 26 and the conductor portion 27 may be folded back to such an extent that the one end 28 and the other end 29 are adjacent to the conductor portions 26 and 27 between the first folded portion 21 and the second folded portion 22, or may be folded back to such an extent that the one end 28 and the other end 29 are adjacent to the second conductor portion 30.

Both ends 28, 29 of the first conductor 20 are open, and the first conductor 20 constitutes a U-shaped half-wavelength resonator.

As in the conventional second conductor portion 30X shown in fig. 2, one end 38 of the second conductor portion 30 is connected to the first folded portion 21 of the first conductor portion 20 and extends in the Y direction continuously from the first conductor portion 20. The second conductor portion 30 has the other end 39 opened, and the second conductor portion 30 and the first conductor portion 20 constitute a linear (l-shaped) half-wavelength resonator.

fig. 10A is a schematic diagram of the current distribution of the even mode resonance of the dual-frequency resonator 10 of the present embodiment. Fig. 10A shows the current distribution of the even mode resonance of the conductor portion 26 on the side of the one end 28 of the first folded portion 21, but the current distribution of the even mode resonance of the conductor portion 27 on the side of the other end 29 of the first folded portion 21 is also the same. The arrows in the figure show the direction of the current.

Since the second folded portion 22 is located at the center between the one end 28 and the other end 29 and the first folded portion 21, in other words, near the center between the first conductor portion 20 and the second conductor portion 30, the current of the even mode resonance is substantially maximized. Thus, as shown in fig. 10A, in the adjacent conductors of the conductor portion 26, currents of even-mode resonances are opposite to each other, and the magnitudes of the currents of the even-mode resonances are substantially equal. Therefore, the magnetic fields radiated to the outside in the even mode resonance cancel each other and become small.

In the odd mode resonance, the conductor portions having a large current flow in the odd mode resonance from the first folded portion 21 to the second folded portion 22 are adjacent to each other, and thus the magnetic fields radiated to the outside in the odd mode resonance cancel each other and become small as described above.

(other Dual-band resonator of this embodiment mode)

Fig. 9B is a plan view of the dual-band resonator of the present embodiment. The dual-band resonator 10 shown in fig. 9B is different from the dual-band resonator 10 of the present embodiment shown in fig. 9A in the structure of the first conductor portion 20.

In the first conductor part 20, in addition to the first conductor part 20 shown in fig. 9A, the folded conductor portions 26 and 27 have a structure in which the third folded portion 23, which is a central portion between the first folded portion 21 and the second folded portion 22, is folded outward at one end 28 and the other end 29. That is, the folded conductor portions 26 and 27 are folded in the direction in which the third folded portion 23 is separated from the second folded portion 22.

In other words, the conductor portion 26 after being folded back has a structure in which it is folded back in the direction of being separated from the conductor portion 27 in the X direction in the third folded-back portion 23, and the conductor portion 27 after being folded back has a structure in which it is folded back in the direction of being separated from the conductor portion 26 in the X direction in the third folded-back portion 23.

In the present embodiment, the first folded portion 21, the one end 28, and the second folded portion 22 are arranged in this order linearly in the X direction in the conductor portion 26, and the first folded portion 21, the other end 29, and the second folded portion 22 are arranged in this order linearly in the X direction in the conductor portion 27.

The first folded portion 21, the one end 28, and the second folded portion 22 may not be linearly arranged in the X direction. The first folded portion 21, the other end 29, and the second folded portion 22 may not be linearly arranged in the X direction. Specifically, the first folded portion 21, the one end 28, and the second folded portion 22 may be arranged in the X direction with a shift in the Y direction. The first folded portion 21, the other end 29, and the second folded portion 22 may be arranged in the X direction with a shift in the Y direction.

The conductor portions 26 and 27 after being folded back may have a structure in which they are further folded back. In this case, the first folded portion 21, the one end 28, the second folded portion 22, and the third folded portion 23 … are arranged in this order in the X direction in the conductor portion 26, and the first folded portion 21, the other end 29, the second folded portion 22, and the third folded portion 23 … are arranged in this order in the X direction in the conductor portion 27.

Fig. 10B is a schematic diagram of the current distribution of the even mode resonance of the other dual-band resonator 10 of the present embodiment. Fig. 10B shows the current distribution of the even mode resonance of the conductor portion 26 on the side of the one end 28 from the first folded portion 21, but the current distribution of the even mode resonance of the conductor portion 27 on the side of the other end 29 from the first folded portion 21 is also the same. The arrows in the figure show the direction of the current.

Since the third folded portion 23 has one end 28 and the other end 29 and a central portion between the first folded portion 21 and the second folded portion 22, in other words, near 1/4 of the first conductor portion 20 and the second conductor portion, the current of the even mode resonance is substantially 1/2 which is the maximum value. Thus, as shown in fig. 10B, in the adjacent conductors in the conductor portion 26, currents of even-mode resonances are opposite to each other, and the magnitudes of the currents of the even-mode resonances are substantially equal. Therefore, the magnetic fields radiated to the outside in the even mode resonance cancel each other and become small.

In the odd mode resonance, the conductor portions having a large current flow in the odd mode resonance from the first folded portion 21 to the third folded portion 23 are adjacent to each other, and thus the magnetic fields radiated to the outside in the odd mode resonance cancel each other and become small as described above.

As described above, according to the dual-band resonator 10 of the present embodiment, the conductor portion 26 and the conductor portion 27 in the first conductor portion 20 are folded back in the direction in which the first folded portion 21 is separated from each other at the one end 28 and the other end 29, and thus the dual-band resonator 10 can be downsized compared to the conventional dual-band resonator 10X.

In addition, according to the dual-band resonator 10 of the present embodiment, the conductor portion 26 and the conductor portion 27 are folded back in the direction in which the third folded back portion 23 is separated from the second folded back portion 22, and thus the dual-band resonator 10 can be further miniaturized.

As described above, by the folded structure of the conductor portions 26 and 27, the currents of the even-mode resonances in the adjacent conductors are opposite to each other, and the magnitudes of the currents of the even-mode resonances are substantially equal to each other, so that the magnetic fields radiated to the outside in the even-mode resonances cancel each other and become smaller.

In this way, when a filter is configured, coupling of not only the odd mode but also the even mode of adjacent resonators is reduced, and the distance between the resonators can be reduced. As a result, the filter can be downsized.

(double band bandpass filter of the present embodiment)

Fig. 11 is a plan view of the dual band bandpass filter of the present embodiment. The dual-band bandpass filter 1 shown in fig. 11 is composed of a conductor having a microstrip line structure formed on a dielectric, as in the conventional dual-band resonator 10X shown in fig. 1. The dual band pass filter 1 includes the feed lines 51 and 52, the two dual band resonators 10, and the waveguide 60, as in the dual band pass filter 1X shown in fig. 5.

The feeder lines 51 and 52 are conductors for inputting and outputting signals, and are disposed so as to sandwich the dual-band resonator 10 in the X direction. The feeder lines 51 and 52 are coupled to the first conductor unit 20 and the second conductor unit 30, respectively.

The dual-band resonator 10 is arranged in the X direction between the power supply lines 51, 52.

The waveguide 60 is a conductor formed by connecting an L-shaped conductor and an inverted L-shaped conductor, and is disposed between the dual-band resonators 10. The waveguide 60 is disposed adjacent to the second conductor portion 30 in the Y direction.

According to the dual band bandpass filter 1, the coupling of the odd mode and the coupling of the even mode are small, and therefore, the interval between the dual band resonators 10 can be reduced. In the present embodiment, the coupling coefficient of the odd mode is adjusted by changing the distance d between the dual-band resonators 10. In this case, the coupling coefficient of the even mode is also adjusted, but this is not sufficient, and therefore, by changing the length l of the waveguide 60, the coupling coefficient of the even mode can be adjusted without affecting the coupling coefficient of the odd mode. Thus, according to the dual band pass filter 1, the coupling coefficient of the odd mode and the coupling coefficient of the even mode can be adjusted.

In addition, according to the dual band pass filter 1, since the power feeding lines 51 and 52 are coupled to the first conductor portion 20 and the second conductor portion 30, respectively, the external Q value of the odd mode and the external Q value of the even mode can be adjusted. The external Q value represents the coupling strength of the supply line to the resonator.

However, in the case of realizing a narrow band filter, it is necessary to reduce coupling between resonators in design, and thus it is necessary to obtain a wide distance between resonators. According to the dual band pass filter 1, since coupling between the resonators is small, the distance between the resonators can be set to be small, and as a result, a small and narrow band dual band pass filter can be realized.

However, in order to effectively utilize frequency resources, steep cutoff characteristics are required for the bandpass filter. In order to obtain a steep blocking characteristic, it is conceivable to form the resonators in multiple layers, but the loss increases, and the performance of the filter deteriorates. Therefore, a superconductor may be used as the first conductor portion and the second conductor portion. In the microwave band, compared with common conductive metals such as copper and the like, the surface resistance of the superconductor is 2-3 orders of magnitude smaller. Therefore, even if the resonator is formed in a plurality of layers, a steep blocking characteristic can be realized while maintaining a low loss.

As described above, according to the dual band bandpass filter 1 of the present embodiment, since the dual band resonator 10 described above is provided, not only the odd mode coupling but also the even mode coupling of the adjacent resonators are reduced, and the distance between the resonators can be reduced. As a result, the filter can be downsized.

further, according to the dual band pass filter 1 of the present embodiment, the distance between the resonators can be reduced as described above, and therefore, a small and narrow band dual band pass filter can be realized.

Further, according to the dual band bandpass filter 1 of the present embodiment, the distance between the resonators can be reduced as described above, and therefore, the resonators can be formed in multiple layers, and a steep blocking characteristic can be realized.

Further, according to the dual band bandpass filter 1 of the present embodiment, since the coupling of not only the odd mode but also the even mode is small, unnecessary skip coupling other than the adjacent resonators can be reduced, and as a result, the multilayered design can be easily performed.

(Dual-band resonator according to modification of the present embodiment)

Fig. 12 is a plan view of a dual-band resonator according to a modification of the present embodiment. As shown in fig. 12, the dual-band resonator 10 shown in fig. 9B may also adopt a stepped-impedance configuration. Specifically, the dual-band resonator 10 may have a structure in which the first conductor portion 20 is thinned and the second conductor portion 30 is thickened. This enables frequency adjustment of the even mode and the odd mode. Further, the resonator can be further miniaturized.

Further, a recess 35 may be provided at an end portion of the second conductor portion 30 on the other end 39 side. By adjusting the depth of the groove of the recess 35, the frequency of the even-mode resonance can be finely adjusted as compared with the case where the entire end portion of the other end 39 of the second conductor portion 30 is adjusted. The formation position of the recess 35 is preferably the center of the end portion on the other end 39 side of the second conductor portion 30. This allows fine adjustment of the frequency of the even mode resonance without affecting the adjustment of the coupling coefficient of the even mode by the waveguide 60 shown in fig. 11.

Instead of the concave portion 35, a convex portion may be provided at the end portion of the second conductor portion 30 on the other end 39 side. In this case, the frequency of the even mode resonance can be finely adjusted by adjusting the projection length of the convex portion.

(Dual band bandpass filter according to the modification of the present embodiment)

fig. 13 is a plan view of a dual band bandpass filter according to a modification of the present embodiment. As shown in fig. 13, the dual-band resonator 10 of fig. 12 may be employed as the dual-band resonator 10 in the dual-band bandpass filter 1 shown in fig. 11.

Further, an I-shaped waveguide 70 may be further provided. The waveguide 70 is disposed in the vicinity of the second folded portion 22 and/or the vicinity of the third folded portion 23 so as to extend in the X direction between the dual-band resonators 10. Thereby enabling fine tuning of the odd mode coupling coefficient.

(evaluation results of examples)

The dual band bandpass filter 1 of the embodiment was designed and manufactured, and evaluated.

Fig. 14 is a plan view of the dual band bandpass filter 1 of the embodiment designed and manufactured in this evaluation. As shown in fig. 14, the dual band pass filter 1 of the embodiment designed and manufactured in this evaluation includes 10 layers of dual band resonators 10 according to the structure of the dual band pass filter 1 shown in fig. 13.

As shown in fig. 14, the distance d between the dual-band resonators 10, the presence or absence and the length of the waveguide 70, and the depth of the recess 35 were adjusted in each layer.

The design conditions and design parameters are as follows.

Resonant frequency of odd mode 1.5GHz

Frequency bandwidth of odd mode 15MHz

Fluctuation of odd mode 0.03dB

resonance frequency of even mode 2.0GHz

Frequency bandwidth of even mode 20MHz

Even mode fluctuation of 0.03dB

Fig. 15A to 15C show simulation results of the S parameter at the time of design. Fig. 15A shows S21 (pass characteristic) of the embodiment of fig. 14, fig. 15B shows S21 (pass characteristic) and S11 (reflection characteristic) of the XVB part (near the odd mode resonance frequency) of fig. 15A in an enlarged manner, and fig. 15C shows S21 (pass characteristic) and S11 (reflection characteristic) of the XVC part (near the even mode resonance frequency) of fig. 15A in an enlarged manner. The simulations of fig. 15A to 15C use an electromagnetic field analysis simulator SONNET EM (manufactured by SONNET research).

Fig. 16A to 16C show the actual measurement results of the S parameter of the manufactured example. Fig. 16A shows S21 (pass characteristic) of the embodiment of fig. 14, fig. 16B shows S21 (pass characteristic) and S11 (reflection characteristic) of the XVIB portion (near the odd mode resonance frequency) of fig. 16A in an enlarged manner, and fig. 16C shows S21 (pass characteristic) and S11 (reflection characteristic) of the XVIC portion (near the even mode resonance frequency) of fig. 16A in an enlarged manner. In the measurement of fig. 16A to 16C, a network analyzer E5063A (manufactured by deluxe corporation) was used.

From fig. 15A to 15C and fig. 16A to 16C, measurement results substantially the same as the simulation results were obtained, and the effectiveness of the method of the example was confirmed.

Further, by making the dual-band resonator 10 into 10 layers, steep blocking characteristics are realized.

The size of the dual-band resonator 10 of the embodiment of fig. 14 is 2.7mm (X direction) × 10.6mm (Y direction), and the size of the dual-band bandpass filter 1 of the embodiment of fig. 14 is 39.35mm (X direction) × 15.8mm (Y direction). Thus, the dual-band resonator 10 and the dual-band-pass filter 1 of the embodiment can be made smaller than the dual-band resonator 10X and the dual-band-pass filter 1X of the conventional example described above.

In the embodiment, the resonator length is adjusted so that the odd mode resonator resonates at the low frequency side and the even mode resonator resonates at the high frequency side, but the resonator length may be adjusted so that the odd mode resonator resonates at the high frequency side and the even mode resonator resonates at the low frequency side.

the embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments and can be modified as appropriate.

Description of the symbols

1. 1X-band pass filter, 10X-dual-frequency resonator, 11-dielectric, 12-ground conductor, 20X-first conductor section, 21-first folded section, 22-second folded section, 23-third folded section, 26-conductor section on one end side, 27-conductor section on the other end side, 28-one end, 29-the other end, 30X-second conductor section, 35-recess, 38-one end, 39-the other end, 40-boundary surface, 51X, 52X-power feed line, 60X, 70X-waveguide.