CN111478679A - High-performance duplexer based on SAW and BAW - Google Patents

Abstract

A high-performance duplexer based on SAW and BAW of the present invention belongs to the technical field of duplexers. comprising a first filter for filtering the transmitted radio frequency signal, namely the bulk acoustic wave filter BAW, and a second filter for receiving and filtering the radio frequency signal, namely the surface acoustic wave filter SAW; by using the SAW in the final stage of the first filter A resonator that can suppress the deterioration of second-order distortion and harmonic characteristics. Also by combining the SAW resonator of the first filter in series with the SAW resonator of the second filter in the same SAW chip, antenna matching can be improved relative to other duplexers. At the same time, configuring the loop to generate an out-of-phase signal with the target signal at a specific frequency to suppress the target signal improves the stability and high out-of-band rejection of the duplexer and reduces the size.

Description

A High Performance Duplexer Based on SAW and BAW

technical field

The invention belongs to the technical field of duplexers, in particular to a high-performance duplexer based on SAW and BAW.

Background technique

Acoustic filters are widely used in radio frequency electronic systems. For example, filters in the radio frequency front end of a mobile phone typically include an acoustic filter, two of which can be combined into a duplexer. The general duplexer is composed of a spiral vibrating cavity. Due to its high operating frequency and great influence on the distribution parameters, it is often made into a sealed casing. Each signal feeder is made of coaxial cable with better shielding effect, and the cavity shape is also A certain finish is required. In many LC duplexer circuit applications, it is necessary to use a higher-level filter comprehensive design to meet the design requirements. It has also increased, so that it is difficult to meet the requirements of the application of the existing size of the chip components.

For wireless telephones, the space provided by automobiles is limited, and the wiring and heat dissipation of wireless telephones need to be considered. Therefore, under the premise of meeting other technical indicators, it is necessary to miniaturize the duplexer.

SUMMARY OF THE INVENTION

1. The technical problem to be solved by the invention

The purpose of the present invention is to solve the problem that the existing duplexer needs to use a higher-level filter comprehensive design to achieve high out-of-band suppression, high stability and other indicators, which will lead to excessive volume, and at the same time, the existing size of the patch components It is also difficult to meet the demand problem.

2. Technical solutions

In order to achieve the above object, the technical scheme provided by the invention is:

A high-performance duplexer based on SAW and BAW of the present invention, comprising:

The first filter for filtering the transmitted radio frequency signal is the bulk acoustic wave filter BAW and the second filter for receiving the radio frequency signal and filtering is the surface acoustic wave filter SAW;

The first filter includes an S1 resonator, an S2 resonator, an S3 resonator, an S4 resonator, and an RA1 resonator connected in series in sequence, and the S1 resonator is connected in parallel with a P1 resonator and a P2 resonator. A P3 resonator and a P4 resonator are connected in parallel at both ends of the resonator, and an RA2 resonator is connected in parallel between the S4 resonator and the RA1 resonator;

The second filter includes a B1 resonator, a B3 resonator, a B5 resonator, a B7 resonator and a B9 resonator in series, and the second filter further includes: connected between the B1 resonator and the B3 resonator B2 resonator, B4 resonator connected between B3 resonator and B5 resonator, B6 resonator connected between B5 resonator and B7 resonator, B8 connected between B7 resonator and B9 resonator Resonators, the B2 resonator, B4 resonator, B6 resonator and B8 resonator are connected in parallel with each other.

Preferably, the first filter is connected with a first loop, the first loop and the first filter are connected through a capacitor, and the first loop is coupled to the input end S1 resonator of the first filter and the output RA1 resonator.

Preferably, the second filter is further coupled with a second loop, and the second loop is coupled to the input B1 resonator and the output B9 resonator of the second filter.

Preferably, both the first loop and the second loop include several SAW elements, the SAW elements are SAW resonators or SAW delay lines, and each SAW element includes an interdigital transducer electrode.

Preferably, an input end of the first filter is connected to a transmission signal input node TX.

Preferably, the output end of the second filter is connected to a received signal output node RX.

Preferably, an antenna port ANT is connected between the first filter and the second filter.

Preferably, the first loop and the second loop are configured to generate an out-of-phase signal with the target signal at a specific frequency to suppress the target signal, improving out-of-band rejection and duplexer stability.

Preferably, an inductor TXL is connected in series between the transmit input node TX and the first filter.

Preferably, the final stage of the first filter uses a SAW resonator by combining the series SAW resonator of the first filter and the SAW resonator of the first filter in the same SAW chip.

3. Beneficial effects

Adopting the technical scheme provided by the present invention, compared with the prior art, has the following beneficial effects:

A high-performance duplexer based on SAW and BAW of the present invention, the first filter for filtering the transmitted radio frequency signal, namely the bulk acoustic wave filter BAW, and the second filter for receiving and filtering the radio frequency signal, namely the surface acoustic wave Filter SAW; the first filter includes S1 resonator, S2 resonator, S3 resonator, S4 resonator and RA1 resonator connected in series in sequence, P1 resonator and P2 resonator are connected in parallel at both ends of S1 resonator, S3 resonator There are P3 resonators and P4 resonators in parallel at both ends, and RA2 resonators are connected in parallel between S4 resonators and RA1 resonators; the second filter includes B1 resonators, B3 resonators, B5 resonators, and B7 resonators in series. and the B9 resonator, the second filter further comprises: a B2 resonator connected between the B1 resonator and the B3 resonator, a B4 resonator connected between the B3 resonator and the B5 resonator, a B5 resonator connected to and The B6 resonator between the B7 resonators, the B8 resonator connected between the B7 resonator and the B9 resonator, the B2 resonator, the B4 resonator, the B6 resonator and the B8 resonator are connected in parallel with each other. By using the SAW resonator in the final stage of the first filter, the second-order distortion and the deterioration of the harmonic characteristics can be suppressed. Also by combining the SAW resonator of the first filter in series with the SAW resonator of the second filter in the same SAW chip, antenna matching can be improved relative to other duplexers. At the same time, configuring the loop to generate an out-of-phase signal with the target signal at a specific frequency to suppress the target signal improves the stability and high out-of-band rejection of the duplexer and reduces the size.

Description of drawings

FIG. 1 is a schematic structural diagram of a high-performance duplexer based on SAW and BAW according to the present invention.

FIG. 2 is a schematic structural diagram of a coupling loop of a high-performance duplexer based on SAW and BAW according to the present invention.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be more fully described below with reference to the related drawings, in which several embodiments of the present invention are given, however, the present invention can be implemented in many different forms and is not limited to this The described embodiments are, rather, provided so that this disclosure will be thorough and complete.

It should be noted that when an element is referred to as being "fixed" to another element, it can be directly on the other element or intervening elements may also be present; when an element is referred to as being "connected" to another element, it may be be directly connected to another element or intervening elements may be present; the terms "vertical", "horizontal", "left", "right" and similar expressions are used herein for illustrative purposes only.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the present invention; the terms used herein in the description of the present invention are only used to describe specific embodiments is not intended to limit the invention; as used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Example 1

Referring to FIG. 1 , a high-performance duplexer based on SAW and BAW of the present embodiment includes a first filter for filtering a transmitted radio frequency signal, namely a bulk acoustic wave filter BAW, and a filter for receiving and filtering radio frequency signals. The second filter is the surface acoustic wave filter SAW;

The first filter includes an S1 resonator, an S2 resonator, an S3 resonator, an S4 resonator, and an RA1 resonator connected in series in sequence, and the S1 resonator is connected in parallel with a P1 resonator and a P2 resonator. A P3 resonator and a P4 resonator are connected in parallel at both ends of the resonator, and an RA2 resonator is connected in parallel between the S4 resonator and the RA1 resonator;

The second filter includes a B1 resonator, a B3 resonator, a B5 resonator, a B7 resonator and a B9 resonator in series, and the second filter further includes: connected between the B1 resonator and the B3 resonator B2 resonator, B4 resonator connected between B3 resonator and B5 resonator, B6 resonator connected between B5 resonator and B7 resonator, B8 connected between B7 resonator and B9 resonator Resonators, the B2 resonator, B4 resonator, B6 resonator and B8 resonator are connected in parallel with each other.

Based on a duplexer composed of a highly integrated surface acoustic wave SAW filter and a bulk acoustic wave BAW filter, by using a SAW resonator in the final stage of the first filter, second-order distortion and deterioration of harmonic characteristics can be suppressed. In addition, antenna matching can be improved relative to other duplexers by combining the SAW resonator of the first filter in series with the SAW resonator of the second filter in the same SAW chip. At the same time, the loop is configured to generate an inverted signal with the target signal at a specific frequency to suppress the target signal, which improves the stability of the duplexer and high out-of-band rejection and reduces the size of the duplexer.

The first filter of this embodiment is connected with a first loop, the first loop and the first filter are connected through a capacitor, and the first loop is coupled to the input end S1 of the first filter, the resonator and the first filter. Output RA1 resonator.

The second filter of this embodiment is also coupled with a second loop, which is coupled to the input B1 resonator and the output B9 resonator of the second filter.

Both the first loop and the second loop in this embodiment include several SAW elements, the SAW elements are SAW resonators or SAW delay lines, and each SAW element includes an interdigital transducer electrode.

An input end of the first filter in this embodiment is connected to a transmission signal input node TX.

The output end of the second filter in this embodiment is connected to the received signal output node RX.

An antenna port ANT is connected between the first filter and the second filter in this embodiment.

The first loop and the second loop of this embodiment are configured to generate an out-of-phase signal with the target signal at a specific frequency to suppress the target signal, improving out-of-band rejection and duplexer stability.

In this embodiment, an inductor TXL is connected in series between the transmitting input node TX and the first filter, which can improve input matching and reduce return loss.

The final stage of the first filter of this embodiment uses a SAW resonator, which is achieved by combining the series SAW resonator of the first filter and the SAW resonator of the first filter in the same SAW chip. The SAW resonator is used in the final stage, which can suppress the deterioration of the second-order distortion and harmonic characteristics. Also by combining the series SAW resonator of the first filter with the SAW resonator of the first filter in the same SAW chip, antenna matching can be improved relative to other duplexers.

The above-mentioned embodiment only expresses a certain embodiment of the present invention, and its description is more specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention; it should be pointed out that for those of ordinary skill in the art Said that, on the premise of not departing from the concept of the present invention, several modifications and improvements can be made, which all belong to the protection scope of the present invention; therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (10)

1. a high-performance duplexer based on SAW and BAW, is characterized in that: comprising: The first filter for filtering the transmitted radio frequency signal is the bulk acoustic wave filter BAW and the second filter for receiving the radio frequency signal and filtering is the surface acoustic wave filter SAW; The first filter includes an S1 resonator, an S2 resonator, an S3 resonator, an S4 resonator, and an RA1 resonator connected in series in sequence, and the S1 resonator is connected in parallel with a P1 resonator and a P2 resonator. A P3 resonator and a P4 resonator are connected in parallel at both ends of the resonator, and an RA2 resonator is connected in parallel between the S4 resonator and the RA1 resonator; The second filter includes a B1 resonator, a B3 resonator, a B5 resonator, a B7 resonator and a B9 resonator in series, and the second filter further includes: connected between the B1 resonator and the B3 resonator B2 resonator, B4 resonator connected between B3 resonator and B5 resonator, B6 resonator connected between B5 resonator and B7 resonator, B8 connected between B7 resonator and B9 resonator Resonators, the B2 resonator, B4 resonator, B6 resonator and B8 resonator are connected in parallel with each other. 2 . The high-performance duplexer based on SAW and BAW according to claim 1 , wherein the first filter is connected with a first loop, and the first loop and the first filter are connected between the first loop and the first filter. 3 . By capacitive connection, the first loop is coupled to the input S1 resonator and the output RA1 resonator of the first filter. 3. A high-performance duplexer based on SAW and BAW according to claim 1, wherein the second filter is further coupled with a second loop, and the second loop is coupled to the first Two filters have input B1 resonator and output B9 resonator. 4. A high-performance duplexer based on SAW and BAW according to claim 1, wherein the first loop and the second loop both comprise several SAW elements, and the SAW elements are SAW resonators or SAW delay line, each SAW element includes interdigital transducing electrodes. 5 . The high-performance duplexer based on SAW and BAW according to claim 1 , wherein the input end of the first filter is connected with a transmission signal input node TX. 6 . 6 . The high-performance duplexer based on SAW and BAW according to claim 1 , wherein the output end of the second filter is connected to a received signal output node RX. 7 . 7 . The high-performance duplexer based on SAW and BAW according to claim 1 , wherein an antenna port ANT is connected between the first filter and the second filter. 8 . 8. A high-performance duplexer based on SAW and BAW according to claim 4, wherein the first loop and the second loop are configured to generate an inversion of the target signal at a specific frequency signal to suppress the target signal, improving out-of-band rejection and duplexer stability. 9 . The high-performance duplexer based on SAW and BAW according to claim 5 , wherein an inductor TXL is connected in series between the transmit input node TX and the first filter. 10 . 10. A high-performance duplexer based on SAW and BAW according to claims 1 to 8, characterized in that: a SAW resonator is used in the last stage of the first filter, by resonating the series SAW of the first filter The SAW resonator is incorporated in the same SAW chip as the SAW resonator of the first filter.

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