CN109639255B

CN109639255B - Duplexer

Info

Publication number: CN109639255B
Application number: CN201811592051.2A
Authority: CN
Inventors: 庞慰; 蔡华林
Original assignee: Tianjin University; ROFS Microsystem Tianjin Co Ltd
Current assignee: Tianjin University; ROFS Microsystem Tianjin Co Ltd
Priority date: 2018-12-25
Filing date: 2018-12-25
Publication date: 2022-07-12
Anticipated expiration: 2038-12-25
Also published as: CN109639255A

Abstract

The present invention provides a duplexer, including: a transmission filter connected between a transmission terminal and an antenna terminal and including a series resonator and a parallel resonator connected in a ladder form; and a reception filter connected between a reception end and the antenna end and including a series resonator and a parallel resonator connected in a ladder form, wherein the LWR resonator is connected on a series branch of the TX or RX or the LWR resonator is connected on a parallel branch of the TX or RX and connected with a ground terminal; the LWR resonator is introduced into the structural design of the filter and the duplexer and applied to the structures of the piezoelectric filter and the duplexer to improve the performance of the piezoelectric filter and the duplexer, the LWR resonance frequency points are utilized to adjust the impedance characteristics, flexible frequency and piezoelectric coupling coefficients, different frequencies and piezoelectric coupling coefficients are combined, and required impedance conversion is realized at specific frequency points.

Description

Duplexer

Technical Field

The invention relates to the field of semiconductors and micro electro mechanical systems, in particular to a duplexer.

Background

With the rapid development of wireless communication systems, the performance requirements of the radio frequency front end are becoming more and more stringent. And wireless communication systems are moving towards multi-function, multi-band, multi-protocol, which presents a higher challenge to the rf front-end in wireless communication devices. As a very important module in the rf front-end, the performance of the filter duplexer plays a decisive role in the rf front-end performance. There is therefore a great need for continued improvements in the performance of filter duplexers.

In the field of radio frequency communication, Film Bulk Acoustic Wave Filters (FBARs) are increasingly gaining attention due to their small size, high roll-off, and low insertion loss characteristics, and market share is continuously increasing. However, the frequency of the resonator constituting the FBAR filter is realized by adjusting the thickness of the physical layer, the adjustable range is limited, and in the case where the adjustable range is too wide, the resonator performance is difficult to be secured. In addition, the piezoelectric coupling coefficient of the resonator depends substantially on the thickness and material parameters of the piezoelectric medium layer, and is difficult to adjust on the same filter. The limited range of frequency and piezoelectric coupling coefficient implementations limits the overall performance gain of the filter.

Therefore, how to adjust the frequency and the piezoelectric coupling coefficient through the LWR resonator to improve the performance of the piezoelectric filter and the duplexer is a technical problem that needs to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the present invention provides a duplexer.

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

a transmission filter connected between a transmission terminal and an antenna terminal and including a series resonator and a parallel resonator connected in a ladder form; and

a reception filter connected between a reception end and the antenna end and including a series resonator and a parallel resonator connected in a ladder form,

the LWR resonator is connected to the series branch of the TX or RX or the LWR resonator is connected to the parallel branch of the TX or RX and connected to the ground terminal.

The LWR lamb wave resonator is introduced into the design of the filter and the duplexer, the LWR resonator is adopted to partially replace the FBAR resonator in the existing filter or duplexer formed by the FBAR resonator, and the number and the position of the LWR resonator replacing the FBAR resonator are not limited. Compared with an FBAR resonator, the frequency and the piezoelectric coupling coefficient can be adjusted by adjusting the thickness of metal and medium, and the ways of adjusting the frequency and the piezoelectric coupling coefficient, such as the plane finger inserting distance of a metal pattern, the duty ratio of the metal pattern and the like, are increased, so that the adjustment range of the frequency and the piezoelectric coupling coefficient is wider.

Further, the LWR resonator is connected in series between the transmission filter or the reception filter and the antenna end.

Still further, the LWR resonators are two groups, one group is connected in series between the transmission filter and the antenna end, and the other group is connected in series between the reception filter and the antenna end.

Still further, the LWR resonator is connected in series between the transmit filter and the antenna end.

Still further, the LWR resonator is connected in series between the receive filter and the antenna end.

Further, the LWR resonator is connected to a parallel branch of any node in the transmit filter or the receive filter and connected to the ground terminal.

Furthermore, the LWR resonators are two groups, and the two groups of LWR resonators are respectively connected to the parallel branch of any node in the transmitting filter and the receiving filter and connected to the ground terminal.

Still further, the LWR resonator is connected to a parallel branch of any node in the transmit filter and to a ground terminal.

Still further, the LWR resonator is connected to a parallel branch of any node in the receive filter and connected to the ground terminal.

Furthermore, the LWR resonators are four groups, two groups of LWR resonators are respectively connected in series between the transmitting filter and the antenna end, and between the receiving filter and the antenna end, and the other two groups of LWR resonators are respectively connected to the parallel branch of any node in the transmitting filter and the receiving filter and connected to the ground terminal.

Furthermore, the LWR resonators are two groups, one group is connected in series between the transmission filter and the antenna end, and the other group is connected to a parallel branch of any node in the transmission filter and connected to the ground end.

Furthermore, the LWR resonators are two groups, one group is connected in series between the receiving filter and the antenna end, and the other group is connected to a parallel branch of any node in the receiving filter and connected to the ground end.

Compared with the prior art, the invention has the beneficial effects that:

the LWR resonator is introduced into the structural design of the filter and the duplexer and applied to the structures of the piezoelectric filter and the duplexer to improve the performance of the piezoelectric filter and the duplexer, the LWR resonance frequency points are utilized to adjust the impedance characteristics, flexible frequency and piezoelectric coupling coefficients, different frequencies and piezoelectric coupling coefficients are combined, and required impedance conversion is realized at specific frequency points.

Compared with the FBAR, the frequency and piezoelectric coupling coefficient can be adjusted by adjusting the thickness of metal and medium, and the ways of adjusting the frequency and piezoelectric coupling coefficient, such as the plane finger insertion distance of the metal pattern, the duty ratio of the metal pattern and the like, are also increased, so that the adjustment range of the frequency and piezoelectric coupling coefficient is wider. On one hand, the LWR is adopted, so that the matching freedom degree is increased in a pass band, and the in-band insertion loss and echo performance are improved. On the other hand, the frequency of the LWR is adjusted at a certain frequency point out of band, and out-of-band suppression and isolation are improved through the change of impedance. And the LWR structure is compatible with the FBAR process, and under the condition of ensuring that the lamination thickness is the same as that of the FBAR, the specific frequency and the piezoelectric coupling coefficient can be realized by adjusting the plane graph.

Drawings

The drawings are included to provide a better understanding of the invention and are not to be construed as unduly limiting the invention. Wherein:

fig. 1 is a circuit configuration diagram of a duplexer according to a first embodiment of the present application.

Fig. 2 is a circuit configuration diagram of a duplexer according to a first modification of the first embodiment of the present application.

Fig. 3 is a circuit configuration diagram of a duplexer according to a second modification of the first embodiment of the present application.

Fig. 4 is a circuit configuration diagram of a duplexer according to a second embodiment of the present application.

Fig. 5 is a circuit configuration diagram of a duplexer according to a first modification of the second embodiment of the present application.

Fig. 6 is a circuit configuration diagram of a duplexer according to a second modification of the second embodiment of the present application.

Fig. 7 is a circuit configuration diagram of a duplexer of a third embodiment of the present application.

Fig. 8 is a circuit configuration diagram of a duplexer of a first modification of the third embodiment of the present application.

Fig. 9 is a circuit configuration diagram of a duplexer according to a second modification of the third embodiment of the present application.

Fig. 10 is a TX band pass-band insertion loss curve of the duplexer of the third embodiment of the present application.

Fig. 11 is an RX band passband insertion loss curve of the duplexer of the third embodiment of the present application.

Fig. 12 is a plan view of the LWR resonator of the present application.

Fig. 13 is a structural diagram of an implementation of the LWR resonator electrode of the present application.

FIG. 14 is a cross-sectional view of one implementation of an LWR resonator electrode of the present application.

Fig. 15 is a structural view of another embodiment of the LWR resonator electrode of the present application.

FIG. 16 is a cross-sectional view of another implementation of the LWR resonator electrode of the present application.

FIG. 17 shows the frequencies corresponding to different inter-finger spacings of LWR resonators according to the present application.

FIG. 18 shows electromechanical coupling coefficients corresponding to different inter-finger spacings of LWR resonators according to the present application.

FIG. 19 shows the frequency of different piezoelectric thicknesses of LWR resonators of the present application.

FIG. 20 shows the electromechanical coupling coefficients for different piezoelectric thicknesses of LWR resonators of the present application.

FIG. 21 is a graph of vibration displacement for the LWR resonator simulation device of the present application in the operating mode.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the technical solution in the embodiment of the present invention will be clearly and completely described below with reference to the drawings in the embodiment of the present invention, and it is obvious that the described embodiment is only a part of the embodiment of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Fig. 1 shows a circuit configuration diagram of a duplexer of a first embodiment of the present application. As shown in fig. 1, a duplexer includes:

a transmission filter 101 connected between a transmission Terminal (TX) and an antenna terminal (ANT) and including a series resonator and a parallel resonator connected in a ladder form; and

a reception filter 102 connected between a reception end (RX) and the antenna end (ANT) and including a series resonator and a parallel resonator connected in a ladder form,

the LWR resonators are two groups, one group of the transmit-side series LWR resonators 103 is connected in series between the transmit filter 101 and the antenna terminal (ANT), and the other group of the receive-side series LWR resonators 104 is connected in series between the receive filter 102 and the antenna terminal (ANT).

Specifically, the transmitting filter 101 and the receiving filter 102 are each composed of a three-stage series resonator and a three-stage parallel resonator, the three-stage series resonator leads out a branch to a ground terminal at a node near an antenna end (ANT) side, and the three-stage parallel resonators are connected in series to the branch.

Fig. 2 is a circuit configuration diagram of a duplexer according to a first modification of the first embodiment of the present application. As shown in fig. 2, a duplexer includes:

a receive filter 102 connected between a receive end (RX) and the antenna end (ANT) and including series resonators and parallel resonators connected in a ladder form,

the transmit side series LWR resonator 103 is connected in series between the transmit filter 101 and the antenna side (ANT).

Specifically, the transmitting filter 101 is composed of a three-stage series resonator and a three-stage parallel resonator, the three-stage series resonator leads out a branch to a ground terminal from a node on one side close to an antenna end (ANT) respectively, and the three-stage parallel resonator is connected in series on the branch respectively; the reception filter 102 is constituted by four-stage series resonators and three-stage parallel resonators that are connected in parallel between two series resonators and one ground terminal, respectively.

Fig. 3 is a circuit configuration diagram showing a duplexer according to a second modification of the first embodiment of the present application. As shown in fig. 3, a duplexer includes:

the receiving-end series LWR resonator 104 is connected in series between the receiving filter 102 and an antenna end (ANT).

Specifically, the transmission filter 101 is composed of four-stage series resonators and three-stage parallel resonators, and the three-stage parallel resonators are respectively connected in parallel between two series resonators and a ground terminal; the receiving filter 102 is composed of three stages of series resonators and three stages of parallel resonators, the three stages of series resonators lead out branches to the ground terminal at nodes near one side of an antenna end (ANT), and the three stages of parallel resonators are connected in series on the branches.

Example 2

Fig. 4 shows a circuit configuration diagram of a duplexer of a second embodiment of the present application. As shown in fig. 4, a duplexer includes:

the

LWR resonators

105 and 106 are connected to the parallel branch of any node in the transmit filter 101 and the receive filter 102, respectively, and are connected to the ground.

Specifically, the transmitting filter 101 and the receiving filter 102 are each composed of a four-stage series resonator and a two-stage parallel resonator, the two-stage parallel resonators are respectively connected in parallel between two series resonators near a transmitting end (TX) and a ground end, and the LWR resonator 105 connected in parallel at the transmitting end is connected in parallel between two series resonators near an antenna end (ANT) and a ground end; the receiving filter 102 is composed of four-stage series resonators and two-stage parallel resonators, the two-stage parallel resonators are respectively connected in parallel between two series resonators near a receiving end (RX) and one ground end, and the receiving-end parallel LWR resonator 106 is connected in parallel between two series resonators near an antenna end (ANT) and one ground end.

Fig. 5 shows a circuit configuration diagram of a duplexer of a first modification of the second embodiment of the present application. As shown in fig. 5, a duplexer includes:

the LWR resonator 105 connected in parallel to the transmitting end is connected to a parallel branch of any node in the transmit filter 101 and is connected to the ground.

Specifically, the transmission filter 101 is composed of four stages of series resonators and two stages of parallel resonators, the two stages of parallel resonators are respectively connected in parallel between two series resonators near a transmission end (TX) and one ground end, and the transmission end parallel LWR resonator 105 is connected in parallel between two series resonators near an antenna end (ANT) and one ground end; the reception filter 102 is constituted by four-stage series resonators and three-stage parallel resonators that are connected in parallel between two series resonators and one ground terminal, respectively.

Fig. 6 shows a circuit configuration diagram of a duplexer of a second modification of the second embodiment of the present application. As shown in fig. 6, a duplexer includes:

the receiving-side parallel LWR resonator 106 is connected to a parallel branch of any node in the receiving filter 102 and is connected to the ground.

Specifically, the transmission filter 101 is composed of four-stage series resonators and three-stage parallel resonators, and the three-stage parallel resonators are respectively connected in parallel between two series resonators and a ground terminal; the receiving filter 102 is composed of four-stage series resonators and two-stage parallel resonators, the two-stage parallel resonators are respectively connected in parallel between two series resonators near a receiving end (RX) and one ground end, and the receiving-end parallel LWR resonator 106 is connected in parallel between two series resonators near an antenna end (ANT) and one ground end.

Example 3

Fig. 7 shows a circuit configuration diagram of a duplexer of a third embodiment of the present application. As shown in fig. 7, a duplexer includes:

the LWR resonators are four groups, one group of the LWR resonators 103 is connected in series between the transmit filter 101 and the antenna end (ANT), one group of the LWR resonators 104 is connected in series between the receive filter 102 and the antenna end (ANT), one group of the LWR resonators 105 is connected in parallel to the transmit filter at any node and connected to the ground, and one group of the LWR resonators 106 is connected in parallel to the receive filter at any node and connected to the ground.

Specifically, the transmission filter 101 and the reception filter 102 are each composed of a three-stage series resonator and a two-stage parallel resonator, and the two-stage parallel resonators are connected in parallel between the two series resonators and one ground terminal, respectively.

Fig. 8 is a circuit configuration diagram showing a duplexer of a first modification of the third embodiment of the present application. As shown in fig. 8, a duplexer includes:

the LWR resonators are two groups, one group of the LWR resonators with transmitting terminals connected in series 103 is connected in series between the transmitting filter 101 and an antenna terminal (ANT), and the other group of the LWR resonators with transmitting terminals connected in parallel 105 is connected in parallel with a branch of any node in the transmitting filter 101 and connected to a ground terminal.

Specifically, the transmission filter 101 is composed of a three-stage series resonator and a two-stage parallel resonator, and the two-stage parallel resonator is respectively connected in parallel between the two series resonators and a ground terminal; the reception filter 102 is constituted by four-stage series resonators and three-stage parallel resonators that are connected in parallel between two series resonators and one ground terminal, respectively.

Fig. 9 shows a circuit configuration diagram of a duplexer of a second modification of the third embodiment of the present application. As shown in fig. 9, a duplexer includes:

the LWR resonators are two groups, one group of receiving end series LWR resonators 104 is connected in series between the transmit filter 101 and an antenna end (ANT), and the other group of receiving end parallel LWR resonators 106 is connected in parallel with a branch of any node in the receive filter 102 and connected to a ground end.

Specifically, the transmission filter 101 is composed of four-stage series resonators and three-stage parallel resonators, and the three-stage parallel resonators are respectively connected in parallel between two series resonators and a ground terminal; the reception filter 102 is constituted by three-stage series resonators and two-stage parallel resonators that are connected in parallel between two series resonators and one ground terminal, respectively.

Fig. 10 shows a TX band pass band insertion loss improvement curve of the duplexer of the third embodiment of the present application. As can be seen from fig. 10, the thin line is the TX band passband insertion loss curve of the duplexer without adding the LWR resonator structure, the thick line is the TX band passband insertion loss curve of the duplexer with adding the LWR resonator structure, the duplexer increases the degree of freedom of frequency and piezoelectric coupling coefficient adjustment by adding the LWR resonator structure, the matching of the passband is better, and therefore the insertion loss is improved.

Fig. 11 shows an RX band passband insertion loss improvement curve of a duplexer according to a third embodiment of the present application, and as can be seen from fig. 11, a thin line is an RX band passband insertion loss curve of the duplexer without adding an LWR resonator structure, a thick line is an RX band passband insertion loss curve of the duplexer with an LWR resonator structure, and the duplexer increases the degree of freedom of adjustment of frequency and piezoelectric coupling coefficients by adding an LWR resonator structure, so that the matching of a passband is better, and therefore the insertion loss is improved.

Here, the LWR resonator will be described. Fig. 12 shows a plan view of the LWR resonator of the present application. As shown in fig. 12, the LWR resonator includes a substrate 1, a cavity 2, a positive electrode 3, a negative electrode 4, and a piezoelectric layer medium, the positive and negative electrodes are connected by interdigitated fingers, and the medium layer is located between the interdigitated fingers of the positive and negative electrodes. The figure shows only one layer of electrode structure, and the LWR resonator has a sandwich structure in practice.

Fig. 13 shows one implementation structure of the LWR resonator electrode of the present application. Fig. 14 shows a sectional view of this LWR resonator electrode. Fig. 15 shows one implementation structure of the LWR resonator electrode of the present application. Fig. 16 shows a sectional view of this LWR resonator electrode.

As can be seen from fig. 13 to 16, fig. 14 and 16 show two implementation forms of LWR resonator electrodes, where the upper electrode and the lower electrode in fig. 14 are both in a finger insertion structure, the upper electrode in fig. 15 is a finger insertion mechanism, and the lower electrode is a monolithic metal structure.

Fig. 17 shows the frequencies corresponding to different inter-finger spacings of the LWR resonators of the present application.

Fig. 18 shows electromechanical coupling coefficients corresponding to different inter-finger distances of the LWR resonators of the present application.

Fig. 19 shows the frequency for different piezoelectric thicknesses of the LWR resonator of the present application.

Fig. 20 shows electromechanical coupling coefficients for different piezoelectric thicknesses of the LWR resonator of the present application.

As can be seen from fig. 17-20, the LWR, as a resonator, is compatible with existing FBAR technology and is integrated in the filter of the FBAR. And the frequency and the electromechanical coupling coefficient kt2 of the FBAR are adjusted flexibly, the problem that the relative adjustment range of the frequency and the electromechanical coupling coefficient of the FBAR is small is solved, the in-band matching is better, and the out-of-band rejection can be improved. The adjustment of the inter-finger pitch is one dimension of the increase because in FBAR the frequency and the electromechanical coupling coefficient kt2 are adjusted only at the vertical stack. On the other hand, in fact, like the FBAR, setting the resonance frequency far from the operating frequency region can be used as a capacitor, and as a capacitor, since the frequency variation range is larger, it is more desirable.

FIG. 21 is a graph of vibration displacement for an LWR resonator simulation device operating mode according to the present application. As can be seen from fig. 21, this device is a device for converting electromagnetic waves into sound waves and then into electromagnetic waves, when the resonant frequency is input at the input end, the device generates sound wave resonance, and the deeper the color in fig. 21, the stronger the surface vibration, which indicates the situation when the device is operating.

In the several embodiments provided in the present application, it should be understood that the disclosed system and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form. The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

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

Although the present invention has been described in detail by referring to the drawings in connection with the preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made on the embodiments of the present invention by those skilled in the art without departing from the spirit and scope of the present invention, and these modifications or substitutions are within the scope of the present invention/any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A duplexer, characterized by comprising:

2. The duplexer according to claim 1, wherein the LWR resonator is connected in series between a transmit filter or a receive filter and an antenna terminal.

3. The duplexer according to claim 2, wherein the LWR resonators are in two groups, one group being connected in series between the transmit filter and the antenna terminal, and the other group being connected in series between the receive filter and the antenna terminal.

4. The duplexer according to claim 2, wherein the LWR resonators are in a group, and are connected in series between a transmission filter and an antenna terminal or between a reception filter and an antenna terminal.

5. The duplexer of claim 1, wherein the LWR resonators are connected to a shunt branch of any node within the transmit filter or the receive filter and to ground.

6. The duplexer of claim 5, wherein the LWR resonators are two groups, and the two groups of LWR resonators are respectively connected to a parallel branch of any node in the transmit filter and the receive filter and connected to the ground terminal.

7. The duplexer of claim 5, wherein the LWR resonators are in a group, connected to a parallel branch from any node in the transmit filter or the receive filter, and connected to ground.

8. The duplexer according to claim 1, wherein the LWR resonators are four groups, two groups of LWR resonators are respectively connected in series between the transmit filter and the antenna terminal, and between the receive filter and the antenna terminal, and the other two groups of LWR resonators are respectively connected to a parallel branch of any node in the transmit filter and the receive filter and connected to the ground terminal.

9. The duplexer of claim 1, wherein the LWR resonators are in two groups, one group being connected in series between the transmit filter and the antenna terminal, and the other group being connected to a shunt branch of any node in the transmit filter and connected to the ground terminal.

10. The duplexer of claim 1, wherein the LWR resonators are two groups, one group being connected in series between the receive filter and the antenna terminal, and the other group being connected to a shunt branch of any node in the receive filter and connected to the ground terminal.