WO2020168958A1

WO2020168958A1 - Band-pass filter, and duplexer

Info

Publication number: WO2020168958A1
Application number: PCT/CN2020/074878
Authority: WO
Inventors: 庞慰; 蔡华林
Original assignee: 天津大学; 诺思(天津)微系统有限责任公司
Priority date: 2019-02-19
Filing date: 2020-02-12
Publication date: 2020-08-27
Also published as: CN110071702B; CN110071702A

Abstract

A band-pass filter and a duplexer. The band-pass filter is located between an input terminal (P1) and an output terminal (P2), and comprises: two parallel-connected resonators (10, 20) and a series-connected resonator (30) connected between the two parallel-connected resonators (10, 20), wherein at least one of the parallel-connected resonators (10, 20) and the series-connected resonator (30) is formed by connecting a Lamb wave resonator (LWR) and an inductor, and the other two resonators are formed by connecting an inductor and either a film bulk acoustic resonator (FBAR) or a capacitor. The invention replaces a capacitor at a specific position of the band-pass filter with a Lamb wave resonator (LWR). The LWR effectively improves roll-off by setting a frequency at either side of a passband of the filter, and also enables frequency adjustment via a physical thickness of each layer in the device and a spacing in a surface pattern, thereby providing a wide frequency adjustment range. For large bandwidth applications, especially for an ultra broadband filter consisting of LC filters, the wide frequency range ensures an improvement of roll-off is achieved on two sides by using only one die.

Description

Band pass filter and duplexer

Technical field

The invention relates to the field of semiconductors and micro-electromechanical systems, in particular to a band-pass filter and a duplexer.

Background technique

With the rapid development of wireless communication systems, the performance requirements of the RF front-end are becoming more and more stringent. In addition, the wireless communication system is developing in the direction of multi-function, multi-frequency band, and multi-protocol, which poses a higher challenge to the RF front-end in wireless communication equipment. As a very important module in the RF front-end section, the performance of the filter plays a decisive role in the performance of the RF front-end. Therefore, there is a very urgent need for continuous improvement of filter performance.

The prior art LC bandpass filter usually includes an LC series resonant network on a series path and two parallel resonant networks on a parallel path. Among them, the series resonant network can be replaced with a parallel resonant network or even a single L or C, and the parallel resonant network can also be replaced with a series resonant network or a single L or C. The existing LC bandpass filter can use FBAR to replace the capacitor in it to improve the roll-off, but the frequency adjustment range of FBAR is relatively small. For the wideband filter, such a wide frequency interval cannot be achieved on the same die, so it is necessary Two die, one is set at around 3.3GHz and the other is set at 3.9GHz. This brings about high cost and difficult technical problems.

Therefore, how to use the LWR resonator to improve the roll-off of the bandpass filter and the duplexer and increase the frequency adjustment range of the filter is a technical problem that needs to be solved urgently by those skilled in the art.

Summary of the invention

In view of this, the present invention provides a band-pass filter and a duplexer, which can improve the roll-off of the band-pass filter and the duplexer and increase the frequency adjustment range of the filter by changing the structure of the band-pass filter.

In a first aspect, a band pass filter is provided. The band pass filter is located between an input terminal and an output terminal and includes:

Two sets of parallel resonators and series resonators connected between the two sets of parallel resonators,

Wherein, at least one group of the parallel resonator and the series resonator is formed by connecting a Lamb wave resonator and an inductor, and the other two groups of resonators are formed by one of a thin film bulk acoustic resonator (FBAR) or a capacitor. Connected with inductor.

Preferably, the at least one group of parallel resonators is formed by connecting an inductor and a Lamb wave resonator in parallel.

Preferably, the two sets of parallel resonators are all formed by connecting an inductor and a lamb wave resonator in parallel, and the inductor and the lamb wave resonator in the parallel resonator are both connected to a ground terminal.

More preferably, the two sets of parallel resonators are all formed by connecting an inductor and a Lamb wave resonator in parallel, and the series resonator is formed by connecting an inductor and a capacitor in series.

More preferably, the two sets of parallel resonators are formed by connecting inductors and lamb wave resonators in parallel, and the series resonators are formed by connecting inductors and lamb wave resonators in series.

Preferably, one set of the two sets of parallel resonators is formed by connecting an inductor and a Lamb wave resonator in parallel, and one set is formed by connecting an inductor and a capacitor in parallel. The wave resonators are all connected to the ground terminal.

More preferably, one set of the two sets of parallel resonators is formed by connecting an inductor and a Lamb wave resonator in parallel, and one set is formed by connecting an inductor and a capacitor in parallel, and the series resonator is formed by connecting an inductor and a capacitor in series. Connected.

More preferably, one set of the two sets of parallel resonators is formed by connecting an inductor and a Lamb wave resonator in parallel, and one set is formed by connecting an inductor and a capacitor in parallel, and the series resonator is formed by connecting an inductor and a Lamb wave resonator in parallel. Wave resonators are connected in series.

Preferably, the series resonator is formed by connecting an inductor and a Lamb wave resonator in series, the two sets of parallel resonators are both formed by connecting an inductor and a capacitor in parallel, and the inductor in the parallel resonator, The capacitors are all connected to the ground terminal.

In a second aspect, a duplexer is provided, including:

A transmitting filter connected between the transmitting terminal and the antenna terminal and including a series resonator and a parallel resonator connected in a ladder form; and

A receiving filter which is connected between the receiving end and the antenna end and includes a series resonator and a parallel resonator connected in a ladder form,

Wherein, the transmitting filter and the receiving filter are the above-mentioned band pass filters.

The beneficial effects of the present invention relative to the prior art:

The present invention introduces the LWR lamb wave resonator in the design of the band-pass filter and the duplexer, and replaces the capacitor at a specific position of the band-pass filter with the LWR. On the one hand, the LWR sets the frequency in the passband of the filter. Side can effectively improve the roll-off, on the other hand, LWR can adjust the frequency through the physical thickness of each layer of the device and the spacing of the surface pattern. The frequency adjustment range is relatively wide. For high bandwidth, especially the ultra-wideband filter composed of LC filter In the case of a wide frequency realization, it can be ensured that the roll-off improvement on both sides can be achieved by using the same die. Compared with the previous high roll-off achieved by other types of bulk acoustic wave resonators such as FBAR, due to its wider frequency range, the same die The die is difficult to realize, so the present invention has obvious advantages in improving the roll-off and increasing the frequency adjustment range of the filter.

Description of the drawings

The accompanying drawings are used to better understand the present invention, and do not constitute an improper limitation of the present invention. among them:

Figure 1 is a circuit structure diagram of a prior art band pass filter.

Figure 2 is a simulation curve of a prior art band pass filter.

FIG. 3 is a circuit structure diagram of the band pass filter of the first embodiment of the present application.

Fig. 4 is a simulation curve of the band pass filter of the first embodiment of the present application.

Fig. 5 is a circuit structure diagram of a band pass filter according to a second embodiment of the present application.

Fig. 6 is a circuit structure diagram of a band pass filter according to a third embodiment of the present application.

Fig. 7 is a circuit structure diagram of a band pass filter according to a fourth embodiment of the present application.

FIG. 8 is a circuit structure diagram of a band pass filter according to a fifth embodiment of the present application.

FIG. 9 is a circuit structure diagram of a band pass filter according to a sixth embodiment of the present application.

FIG. 10 is a circuit structure diagram of a band pass filter according to a seventh embodiment of the present application.

detailed description

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described The embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

The existing band-pass filter is shown in FIG. 1. The band-pass filter includes an LC parallel resonator 10 formed by connecting an inductor L1 and a capacitor C1 in parallel between the input terminal P1 and the output terminal P2, and The LC parallel resonator 20 formed by connecting the inductor L2 and the capacitor C2 in parallel, and between the LC parallel resonator 10 and the LC parallel resonator 20, an LC series formed by connecting the inductor L3 and the capacitor C3 in series is connected in series Resonator 30.

Figure 2 shows the simulation results of the existing band-pass filter. It can be seen from FIG. 2 that the frequency adjustment range of the LC bandpass filter in the prior art is relatively narrow. In the wide frequency range of 3.2 GHz and 3.9 GHz, it is impossible to achieve two frequency points to improve roll-off on the same chip.

Example 1

FIG. 3 shows a circuit structure diagram of the band pass filter of the first embodiment of the present application. As shown in Figure 3, a band-pass filter, the band-pass filter between the input terminal P1 and the output terminal P2, includes:

The parallel resonator 10 formed by connecting the inductor L1 and the lamb wave resonator LWR1 in parallel and the parallel resonator 20 formed by connecting the inductor L2 and the lamb wave resonator LWR2 in parallel are connected in parallel with the parallel resonator 10 Between the resonators 20, an LC series resonator 30 formed by connecting an inductor L3 and a capacitor C3 in series is connected in series,

Wherein, the inductor L1, the inductor L2, the lamb wave resonator LWR1, and the lamb wave resonator LWR2 are all connected to the ground terminal, the parallel resonator 10 is connected to the input terminal P1, and the parallel resonator 20 is connected to The output terminal P2 is connected.

Figure 4 shows the simulation results of the existing band-pass filter. It can be seen from Fig. 4 that the roll-off of the band-pass filter in the first embodiment of the present invention around 3.32GHz and 3.86GHz is significantly improved. In the wide frequency range of 3.2GHz and 3.9GHz, both sides can be realized on the same chip. Roll-off improvement.

Example 2

Fig. 5 shows a circuit structure diagram of a band pass filter according to a second embodiment of the present application. As shown in Figure 5, a band-pass filter, the band-pass filter between the input terminal P1 and the output terminal P2, includes:

The parallel resonator 10 formed by connecting the inductor L1 and the lamb wave resonator LWR1 in parallel and the parallel resonator 20 formed by connecting the inductor L2 and the lamb wave resonator LWR2 in parallel are connected in parallel with the parallel resonator 10 Between the resonators 20, a series resonator 30 formed by connecting an inductor L3 and a Lamb wave resonator LWR3 in series is connected in series,

Example 3

Fig. 6 shows a circuit structure diagram of a band pass filter according to a third embodiment of the present application. As shown in Figure 6, a band-pass filter, the band-pass filter between the input terminal P1 and the output terminal P2, includes:

The parallel resonator 10 formed by the parallel connection of the inductor L1 and the Lamb wave resonator LWR1, and the parallel resonator 20 formed by the parallel connection of the inductor L2 and the capacitor C2, between the parallel resonator 10 and the parallel resonator 20 In between, an LC series resonator 30 formed by connecting an inductor L3 and a capacitor C3 in series is connected in series,

Wherein, the inductor L1, the inductor L2, the lamb wave resonator LWR1, and the capacitor C1 are all connected to ground, the parallel resonator 10 is connected to the input terminal P1, and the parallel resonator 20 is connected to the output terminal P2 .

Example 4

Fig. 7 shows a circuit structure diagram of a band pass filter according to a fourth embodiment of the present application. As shown in Figure 7, a band-pass filter, the band-pass filter between the input terminal P1 and the output terminal P2, includes:

The parallel resonator 10 formed by the parallel connection of the inductor L1 and the capacitor C1, and the parallel resonator 20 formed by the parallel connection of the inductor L2 and the lamb wave resonator LWR2, between the parallel resonator 10 and the parallel resonator 20 In between, a series resonator 30 formed by connecting an inductor L3 and a capacitor C3 in series is connected in series,

Wherein, the inductor L1, the inductor L2, the capacitor C1, and the lamb wave resonator LWR2 are all connected to ground, the parallel resonator 10 is connected to the input terminal P1, and the parallel resonator 20 is connected to the output terminal P2 .

Example 5

FIG. 8 shows a circuit structure diagram of a band pass filter according to a fifth embodiment of the present application. As shown in Figure 8, a band-pass filter, the band-pass filter between the input terminal P1 and the output terminal P2, includes:

The parallel resonator 10 formed by the parallel connection of the inductor L1 and the Lamb wave resonator LWR1, and the parallel resonator 20 formed by the parallel connection of the inductor L2 and the capacitor C2, in the parallel resonator 10 and the parallel resonator 20 In between, the series resonator 30 formed by the series connection of the inductor L3 and the lamb wave resonator LWR3 is connected in series,

Wherein, the inductor L1, the inductor L2, the lamb wave resonator LWR1, and the capacitor C2 are all connected to the ground terminal, the parallel resonator 10 is connected to the input terminal P1, and the parallel resonator 20 is connected to the output terminal P2 .

Example 6

FIG. 9 shows a circuit structure diagram of a band pass filter according to a sixth embodiment of the present application. As shown in Fig. 9, a band-pass filter, the band-pass filter between the input terminal P1 and the output terminal P2, includes:

The parallel resonator 10 formed by the parallel connection of the inductor L1 and the capacitor C1, and the parallel resonator 20 formed by the parallel connection of the inductor L2 and the lamb wave resonator LWR2, between the parallel resonator 10 and the parallel resonator 20 In between, the series resonator 30 formed by the series connection of the inductor L3 and the lamb wave resonator LWR3 is connected in series,

Example 7

FIG. 10 shows a circuit structure diagram of a band pass filter according to a seventh embodiment of the present application. As shown in Fig. 10, a band-pass filter, the band-pass filter is between the input terminal P1 and the output terminal P2, and includes:

The parallel resonator 10 formed by connecting the inductor L1 and the capacitor C1 in parallel, and the parallel resonator 20 formed by connecting the inductor L2 and the capacitor C2 in parallel are connected in series between the parallel resonator 10 and the parallel resonator 20 There is a series resonator 30 formed by connecting an inductor L3 and a Lamb wave resonator LWR3 in series,

Wherein, the inductor L1, the inductor L2, the capacitor C1, and the capacitor C2 are all connected to the ground terminal, the parallel resonator 10 is connected to the input terminal P1, and the parallel resonator 20 is connected to the output terminal P2.

It should be noted that the capacitors in the above embodiments can be replaced in whole or in part by a film bulk acoustic resonator (FBAR).

In the several embodiments provided in this application, it should be understood that the disclosed system and method may be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there may be other divisions in actual implementation, for example, multiple units or components can be combined or It can be integrated into another system, or some features can be ignored or not implemented. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection may be indirect coupling or communication connection through some interfaces, devices or units, and may be in electrical, mechanical or other forms. The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the objectives of the solutions of the embodiments.

In addition, the functional units in the various embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units may be integrated into one unit.

Although the present invention has been described in detail by referring to the drawings and in conjunction with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, those of ordinary skill in the art can make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions should be within the scope of the present invention/anything. Those skilled in the art can easily conceive of changes or substitutions within the technical scope disclosed by the present invention, and they should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

A band-pass filter, which is located between an input terminal and an output terminal, and is characterized in that it includes:

Two sets of parallel resonators and series resonators connected between the two sets of parallel resonators,

Wherein, at least one group of the parallel resonator and the series resonator is formed by connecting a Lamb wave resonator and an inductor, and the other two groups of resonators are formed by a thin film bulk acoustic wave resonator or a capacitor and an inductor. Connected.
The band pass filter according to claim 1, wherein the at least one set of parallel resonators is formed by connecting an inductor and a Lamb wave resonator in parallel.
The band-pass filter according to claim 2, wherein the two sets of parallel resonators are both formed by connecting inductors and lamb wave resonators in parallel, and the inductors and lamb wave resonators in the parallel resonators The wave resonators are all connected to the ground terminal.
The band-pass filter according to claim 3, wherein the two sets of parallel resonators are formed by connecting inductors and lamb wave resonators in parallel, and the series resonators are connected in series by inductors and capacitors. Become.
The bandpass filter according to claim 3, wherein the two sets of parallel resonators are formed by connecting inductors and lamb wave resonators in parallel, and the series resonators are formed by inductors and lamb wave resonators. Resonators are connected in series.
The bandpass filter according to claim 2, wherein the two sets of parallel resonators are formed by connecting an inductor and a Lamb wave resonator in parallel, and the set is formed by connecting an inductor and a capacitor in parallel. , The inductor and the lamb wave resonator in the parallel resonator are both connected to the ground terminal.
The bandpass filter according to claim 6, wherein the two sets of parallel resonators are formed by connecting inductors and lamb wave resonators in parallel, and the other set is formed by connecting inductors and capacitors in parallel. The series resonator is formed by connecting an inductor and a capacitor in series.
The bandpass filter according to claim 6, wherein the two sets of parallel resonators are formed by connecting inductors and lamb wave resonators in parallel, and the other set is formed by connecting inductors and capacitors in parallel. The series resonator is formed by connecting an inductor and a Lamb wave resonator in series.
The bandpass filter according to claim 2, wherein the series resonator is formed by connecting an inductor and a Lamb wave resonator in series, and the two sets of parallel resonators are both connected in parallel by an inductor and a capacitor As a result, the inductors and capacitors in the parallel resonator are all connected to the ground terminal.
A duplexer, characterized in that it comprises:

A transmitting filter connected between the transmitting terminal and the antenna terminal and including a series resonator and a parallel resonator connected in a ladder form; and

A receiving filter which is connected between the receiving end and the antenna end and includes a series resonator and a parallel resonator connected in a ladder form,

Wherein, the transmitting filter and the receiving filter are any one of the bandpass filters of claims 1-9.