阅读说明：本技术 多工器和改善多工器隔离度的方法以及通信设备 (Multiplexer and method for improving isolation of multiplexer and communication equipment ) 是由 蔡华林 于 2020-10-30 设计创作，主要内容包括：本发明提出了一种调整滤波器电路的方法和滤波器、多工器、通信设备,有助于提高多工器内部的隔离度,以及改善多工器内各滤波器的滚降性能。该多工器包含多个体声波滤波器,各所述滤波器包含至少2个对地电感,所述至少2个对地电感中的前级对地电感位于所述多工器的封装基板的中部,后级对地电感位于该封装基板的两侧。多个滤波器的输入匹配电感位于封装基板的中部,输出匹配电感位于该封装基板的两侧。(The invention provides a method for adjusting a filter circuit, a filter, a multiplexer and communication equipment, which are beneficial to improving the isolation degree in the multiplexer and improving the roll-off performance of each filter in the multiplexer. The multiplexer comprises a plurality of bulk acoustic wave filters, each filter comprises at least 2 grounding inductors, the front-stage grounding inductor of the at least 2 grounding inductors is positioned in the middle of a packaging substrate of the multiplexer, and the rear-stage grounding inductors are positioned on two sides of the packaging substrate. The input matching inductors of the filters are positioned in the middle of the packaging substrate, and the output matching inductors are positioned on two sides of the packaging substrate.)

1. A multiplexer comprising a plurality of bulk acoustic wave filters, each of said filters comprising at least 2 inductors to ground,

the front-stage grounding inductor in the at least 2 grounding inductors is positioned in the middle of the packaging substrate of the multiplexer, and the rear-stage grounding inductors are positioned on two sides of the packaging substrate.

2. The multiplexer of claim 1,

the multiplexer also comprises an input matching inductor and an output matching inductor;

the input matching inductor is positioned in the middle of the packaging substrate, and the output matching inductors are positioned on two sides of the packaging substrate.

3. The multiplexer of claim 1 or 2, wherein the width of the middle portion is 25% to 75% of the width of the package substrate.

4. The multiplexer of claim 1 or 2, wherein the front stage ground-to-ground inductor and the back stage ground-to-ground inductor are integrated in different layers of a package substrate, respectively.

5. The multiplexer of claim 1 or 2,

the multiplexer comprises 4 filters;

the inductors in different filters are respectively positioned in four corner areas of the packaging substrate, and the length of each corner area accounts for 30-80% of the length of the packaging substrate.

6. The multiplexer of claim 1 or 2, wherein the inductance of the front stage ground inductor is less than the inductance of the back stage ground inductor.

7. The multiplexer of claim 6, wherein the inductance of the front stage ground-to-ground inductor is 0% to 60% of the inductance of the rear stage ground-to-ground inductor.

8. The multiplexer of claim 6, wherein the inductance of the front stage ground-to-ground inductor is 0% to 40% of the inductance of the rear stage ground-to-ground inductor.

9. A method of improving isolation in a multiplexer, said multiplexer comprising a plurality of bulk acoustic wave filters, each of said filters comprising at least 2 ground inductances, the method comprising:

dividing the earth inductance in each filter into a front-stage earth inductance and a rear-stage earth inductance, wherein the front-stage earth inductance is close to the input end of the filter, and the rear-stage earth inductance is close to the output end of the filter;

the front stage grounding inductance is arranged in the middle of the packaging substrate of the multiplexer, and the rear stage grounding inductance is arranged on two sides of the packaging substrate.

10. The method of claim 9, wherein the multiplexer further comprises an input matching inductor and an output matching inductor; and arranging input matching inductors in the middle of the packaging substrate, and arranging output matching inductors on two sides of the packaging substrate.

11. A method according to claim 9 or 10, characterized by reducing the choice of inductance value for the pre-inductor to reduce mutual inductive coupling between the pre-inductor and the post-inductor and/or the output inductor.

12. The method of claim 9 or 10, wherein the width of the middle portion is 25% to 75% of the width of the package substrate.

13. The method of claim 9 or 10, wherein the multiplexer comprises 4 filters, the inductors are located at two sides of the package substrate, the inductors in different filters are located at four corner regions of the package substrate, and the length of each corner region is 30% to 80% of the length of the package substrate.

14. The method according to claim 9 or 10, wherein the front stage ground inductor and the rear stage ground inductor are integrated in different layers of a package substrate respectively.

15. A communication device comprising a multiplexer according to any one of claims 1 to 8.

Technical Field

The present invention relates to the field of filtering technologies, and in particular, to a multiplexer, a method for improving isolation of the multiplexer, and a communication device.

Background

The recent trend toward miniaturization and high performance of communication devices has been increasing, posing even greater challenges to rf front-ends. A typical structure of a general filter is shown in fig. 1, and fig. 1 is a schematic view of a structure of an acoustic wave filter according to the related art. In this filter 10, inductors 121 and 122 and a plurality of resonators (generally referred to as series resonators) 101 to 104 are provided between an input terminal 131 and an output terminal 132, and resonators 111 to 113 (generally referred to as parallel resonators) and inductors 123 to 125 are provided in a plurality of arms (generally referred to as parallel arms) between a connection point of each series resonator and a ground terminal.

Fig. 2 is a schematic diagram of the main components of a multiplexer according to the prior art, as shown in fig. 2, the multiplexer includes filters 21 to 24, and input matching inductors Lant, Lm, Lin1, Lin2, Lin3, and Lin 4. The matching inductor is one of matching circuits for matching filters of a plurality of frequency bands to a specified port resistance value, for example, 50 ohms.

Mutual inductance coupling can be formed among the various inductors, the mutual inductance coupling influences the isolation degree inside the device, and the roll-off performance of the filter is reduced.

Disclosure of Invention

Accordingly, the present invention provides a multiplexer, a method for improving isolation of the multiplexer, and a communication device, which are helpful for improving isolation inside the multiplexer and improving roll-off performance of each filter inside the multiplexer.

The invention provides the following technical scheme:

a multiplexer comprises a plurality of bulk acoustic wave filters, each filter comprises at least 2 grounding inductors, the front-stage grounding inductor of the at least 2 grounding inductors is positioned in the middle of a packaging substrate of the multiplexer, and the rear-stage grounding inductors are positioned on two sides of the packaging substrate.

Optionally, the multiplexer further comprises an input matching inductor and an output matching inductor; the input matching inductor is positioned in the middle of the packaging substrate, and the output matching inductors are positioned on two sides of the packaging substrate.

Optionally, the width of the middle portion is 25% to 75% of the width of the package substrate.

Optionally, the front stage ground inductor and the rear stage ground inductor are respectively integrated on different layers of the package substrate.

Optionally, the multiplexer includes 4 filters located in the inductors on both sides of the package substrate; the inductors in different filters are respectively positioned in four corner areas of the packaging substrate, and the length of each corner area accounts for 30-80% of the length of the packaging substrate.

Optionally, an inductance value of the front stage ground inductor is smaller than an inductance value of the rear stage ground inductor.

Optionally, the inductance value of the front stage ground inductor is 0% to 60% of the inductance value of the rear stage ground inductor.

Optionally, the inductance value of the front stage ground inductor is 0% to 40% of the inductance value of the rear stage ground inductor.

A method of improving isolation in a multiplexer, the multiplexer comprising a plurality of bulk acoustic wave filters, each of the filters comprising at least 2 inductors to ground, the method comprising: dividing the earth inductance in each filter into a front-stage earth inductance and a rear-stage earth inductance, wherein the front-stage earth inductance is close to the input end of the filter, and the rear-stage earth inductance is close to the output end of the filter; the front stage grounding inductance is arranged in the middle of the packaging substrate of the multiplexer, and the rear stage grounding inductance is arranged on two sides of the packaging substrate.

Optionally, the multiplexer further comprises an input matching inductor and an output matching inductor; and arranging input matching inductors in the middle of the packaging substrate, and arranging output matching inductors on two sides of the packaging substrate.

Optionally, the selection of the inductance value for the front inductor is reduced to reduce the mutual inductance coupling between the front inductor and the back inductor and/or the output inductor.

Optionally, the width of the middle portion is 25% to 75% of the width of the package substrate.

Optionally, the multiplexer includes 4 filters, the filters are located in the inductors on two sides of the package substrate, the inductors in different filters are located in four corner regions of the package substrate, respectively, and the length of each corner region accounts for 30% to 80% of the length of the package substrate.

Optionally, the front stage ground inductor and the rear stage ground inductor are respectively integrated on different layers of the package substrate.

A communication device comprising a multiplexer according to the invention.

Drawings

For purposes of illustration and not limitation, the present invention will now be described in accordance with its preferred embodiments, particularly with reference to the accompanying drawings, in which:

fig. 1 is a schematic diagram of one structure of an acoustic wave filter according to the prior art;

FIG. 2 is a schematic diagram of the major components of a multiplexer according to the prior art;

FIG. 3 is a schematic diagram of an inductive packet within a multiplexer according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a circuit configuration of a filter related to an embodiment of the present invention;

fig. 5 is a schematic view of arrangement positions of devices in a multiplexer in a package substrate according to an embodiment of the present invention;

fig. 6A and 6B are schematic diagrams illustrating the effect of the arrangement of inductors on a package substrate according to an embodiment of the present invention;

fig. 7A to 7D are schematic diagrams illustrating the effect of roll-off improvement after reducing the pre-stage inductance according to the embodiment of the present invention;

fig. 8A and 8B are schematic views of the effect of the isolation improvement after reducing the front stage inductance according to the embodiment of the present invention.

Detailed Description

In the embodiment of the present invention, filters including at least 2 ground-to-ground inductances are grouped, and different groups are provided at different specific positions on the package substrate. Specifically, the first stage ground-to-ground inductor is close to the input end of the filter, the second stage ground-to-ground inductor is close to the output end of the filter, and in the packaging structure of the multiplexer, the first stage ground-to-ground inductor is arranged in the middle of the packaging substrate of the multiplexer, and the second stage ground-to-ground inductors are arranged on two sides of the packaging substrate.

The matching inductors in the matching circuit in the multiplexer device are also included in the above grouping, the input matching inductors are included in the first group where the front stage ground-to-ground inductors are located, and the output matching inductors are included in the second group where the rear stage ground-to-ground inductors are located. The matching circuit may be a pure inductor, or may be composed of a capacitor and an inductor, and in the multiplexer device, a part of the matching circuit may include a capacitor. Any inductance located in any matching circuit in the multiplexer device may be incorporated into the groupings described above. Taking a case of a multiplexer including 4 filters and each filter including 3 inductors to ground as an example, the division is shown in fig. 3, and fig. 3 is a schematic diagram of inductor grouping in the multiplexer according to an embodiment of the present invention.

IN fig. 3, the multiplexer includes 4 paths, the structures of the filters 31 to 34 are schematically shown as boxes, each of which includes 3 ground-to-ground inductors G1, G2, and G3, and the specific structure is shown IN fig. 4, fig. 4 is a schematic diagram of a circuit structure of a filter according to an embodiment of the present invention, IN which a series branch and 3 parallel branches are provided between an input terminal IN and an output terminal, and the 3 parallel branches include ground-to-ground inductors G1, G2, and G3, respectively. In the embodiment of the present invention, G1 and G2 may be divided into a front stage ground-to-ground inductor, and accordingly G3 is used as a rear stage ground-to-ground inductor, as shown in blocks 41 and 42 in fig. 4. It is also possible to divide G2 and G3 into the later stage ground inductors and only G1 is left as the former stage ground inductor. In addition, the division of the inductances to ground in the individual filters may not necessarily be uniform, that is, for example, G1 and G2 in the filter 31 are divided into a front stage inductance to ground, and then the other filters may be G1 divided into a front stage inductance to ground and G2 and G3 divided into a rear stage inductance to ground.

In this embodiment, the input matching inductors Lant, Lm, Lin1, Lin2, Lin3, and Lin4 are divided into a first group, as shown by box 35 in the figure; the output matching inductors Lout1, Lout2, Lout3, Lout4 are drawn into a second group, as shown in block 36. According to the arrangement in the package substrate described above, the device position in the multiplexer is shown in fig. 5, and fig. 5 is a schematic view of the arrangement position of the device in the multiplexer in the package substrate according to the embodiment of the present invention. The devices in the first group are located in the middle of the package substrate 5, i.e. in the area within the box 51, as seen in the figure, and are specifically provided with the ground-to-ground inductances G1 and G2 of the respective filters, and the matching inductances Lant, Lm, Lin1, Lin2, Lin 3. Width D51 of box 51 is approximately 25% to 75% of width 5D of package substrate 5. The second group of inductors are located on both sides, and because there are 4 filters, the inductors of the second group are again arranged up and down in the figure, and are respectively located in the boxes 52-55, and the length of the boxes 52-55 (the up and down direction in the view of the figure is the length direction, such as the length L52 of the box 52 shown in the figure, and the like) accounts for 30% to 80% of the length 5L of the package substrate. The positions of the five output pins ANT, F1-F4 are also shown in the figure.

Fig. 6A and 6B are schematic diagrams illustrating the effect of the arrangement of inductors on a package substrate according to an embodiment of the present invention. The thick lines in the figure correspond to the embodiments of the present invention, the thin lines correspond to the prior art, fig. 6A shows the isolation between the transmitting end and the receiving end of B3, and fig. 6B shows the isolation between the transmitting end and the receiving end of B1. The improvement in isolation can be seen from fig. 6A and 6B.

In the embodiment of the present invention, the difference from the method of matching ground inductances in the prior art further includes that the front stage inductance is smaller, so as to improve roll-off and isolation. Fig. 7A to 7D are schematic diagrams illustrating the effect of roll-off improvement after reducing the pre-stage inductance according to the embodiment of the present invention. The thick lines in the figure correspond to the embodiment of the present invention, the thin lines correspond to the prior art, fig. 7A corresponds to the B3 transmitting end, fig. 7B corresponds to the B3 receiving end, fig. 7C corresponds to the B1 transmitting end, and fig. 7D corresponds to the B1 receiving end. As can be seen from fig. 7A to 7D, when the pre-stage inductance is set to be small, the roll-off of each filter is improved to different degrees. Fig. 8A and 8B are schematic views of the effect of the isolation improvement after reducing the front stage inductance according to the embodiment of the present invention. The thick lines correspond to the embodiments of the present invention, the thin lines correspond to the prior art, fig. 8A is the isolation contrast between the transmitting end and the receiving end of B3, and fig. 8B is the isolation contrast between the transmitting end and the receiving end of B1. As can be seen from fig. 8A to 8B, when the pre-stage inductance is set to be smaller, the isolation of the multiplexer is improved.

The above-described embodiments should not be construed as limiting the scope of the invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions can occur, depending on design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.