Elastic wave filter, duplexer circuit and electronic communication equipment

Abstract

The invention relates to the technical field of filters, in particular to an elastic wave filter, a duplexer circuit and electronic communication equipment, and the elastic wave filter comprises a first dual-mode surface acoustic wave filter and a second dual-mode surface acoustic wave filter, the first dual-mode surface acoustic wave filter and the second dual-mode surface acoustic wave filter respectively comprise a first interdigital transducer, a second interdigital transducer, a third interdigital transducer, a fourth interdigital transducer, a fifth interdigital transducer and a sixth interdigital transducer which are transversely arranged. Wherein the polarities of the first interdigital transducer, the second interdigital transducer, the third interdigital transducer, the fourth interdigital transducer, the fifth interdigital transducer and the sixth interdigital transducer are designed to be in SG-GS configuration, namely a signal-grounding-signal-grounding polarity arrangement mode.

Description

Technical Field

[0001] The present application relates to the technical field of filters, and in particular to an elastic wave filter, a duplexer circuit and an electronic communication device. Background Art

[0002] As key components in modern communications, piezoelectric crystal-based acoustic elastic wave filters have demonstrated broad application potential in a wide range of industries, including mobile terminals, base stations, and IoT devices. These filters, with their unique miniaturization, low loss, and superior suppression capabilities, have become an indispensable component in improving communication system performance.

[0003] In communication system architectures, elastic wave filters are cleverly divided into two major components: the receive chain (Rx) and the transmit chain (Tx). The receive chain's primary responsibility is to accurately capture and process radio signals from the external environment, and its performance directly impacts the sensitivity and stability of the entire communication system. Given the receive chain's stringent requirements for miniaturization, low loss, and high rejection, the industry generally prefers dual-mode surface acoustic wave filters (DMS) as its core component.

[0004] As the core component of dual-mode surface acoustic wave filters, the interdigital transducer (IDT) is responsible for converting electrical signals into elastic waves and guiding the propagation of these signals across the piezoelectric substrate. Currently, IDT design needs further optimization to achieve greater bandwidth to meet growing performance requirements. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide an elastic wave filter, a duplexer circuit and an electronic communication device to solve the above problems.

[0006] In order to solve the above technical problems, this application adopts the following technical solutions:

[0007] In a first aspect, the present application provides an elastic wave filter, which includes a first dual-mode surface acoustic wave filter and a second dual-mode surface acoustic wave filter, wherein the first dual-mode surface acoustic wave filter includes a first interdigital transducer, a second interdigital transducer, and a third interdigital transducer arranged transversely, and a first reflection grating group respectively arranged on the outside of the first interdigital transducer and the third interdigital transducer, wherein the first interdigital transducer and the second interdigital transducer are connected with SG polarity, and the second interdigital transducer and the third interdigital transducer are connected with GS polarity; the second dual-mode surface acoustic wave filter includes a fourth interdigital transducer, a fifth interdigital transducer, and a sixth interdigital transducer arranged transversely, and a first reflection grating group respectively arranged on the outside of the first interdigital transducer and the third interdigital transducer The fourth interdigital transducer and the second reflection grating group outside the sixth interdigital transducer, the fourth interdigital transducer and the fifth interdigital transducer are connected with SG polarity, and the fifth interdigital transducer and the sixth interdigital transducer are connected with GS polarity; one end of the first interdigital transducer, the second interdigital transducer, the third interdigital transducer, the fourth interdigital transducer, the fifth interdigital transducer and the sixth interdigital transducer are connected to the ground end; the other end of the second interdigital transducer is connected to the signal input end, the other end of the first interdigital transducer is connected to the other end of the fourth interdigital transducer, the other end of the third interdigital transducer is connected to the other end of the sixth interdigital transducer, and the other end of the fourth interdigital transducer is connected to the signal output end.

[0008] Furthermore, the first reflective grid group and the second reflective grid group are not connected to the ground end.

[0009] Furthermore, the IDT includes a plurality of electrode fingers arranged in a transverse direction and crosswise therebetween and a plurality of bus bars arranged in a vertical direction opposite to each other. The electrode fingers are connected to the bus bars, and the electrode fingers all extend in the vertical direction.

[0010] Furthermore, the first electrode finger of the first interdigital transducer close to the second interdigital transducer is connected to the fourth interdigital transducer, and the second electrode finger of the second interdigital transducer close to the first interdigital transducer is connected to the ground end; the third electrode finger of the second interdigital transducer close to the third interdigital transducer is connected to the ground end, and the fourth electrode finger of the third interdigital transducer close to the second interdigital transducer is connected to the sixth interdigital transducer; the fifth electrode finger of the fourth interdigital transducer close to the fifth interdigital transducer is connected to the first interdigital transducer, and the sixth electrode finger of the fifth interdigital transducer close to the fourth interdigital transducer is connected to the ground end; the seventh electrode finger of the fifth interdigital transducer close to the sixth interdigital transducer is connected to the ground end, and the eighth electrode finger of the sixth interdigital transducer close to the fifth interdigital transducer is connected to the third interdigital transducer.

[0011] Furthermore, the number of electrode fingers of the first IDT, the second IDT, the third IDT, the fourth IDT, the fifth IDT or the sixth IDT is greater than or equal to 5, and the number of electrode fingers is an odd number.

[0012] Furthermore, the first IDT, the second IDT, the third IDT, the fourth IDT, the fifth IDT and the sixth IDT have the same number of electrode fingers.

[0013] In a second aspect, the present application provides a duplexer circuit, which includes: a signal input end, a first signal output end and a second signal output end, a first filter circuit is arranged between the signal input end and the first signal output end, and a second filter circuit is arranged between the signal input end and the second signal output end, the first filter circuit and the second filter circuit are connected in parallel, and the first filter circuit and / or the second filter circuit include the elastic wave filter of the first aspect mentioned above.

[0014] In a third aspect, the present application provides an electronic communication device, which includes the elastic wave filter according to the first aspect.

[0015] In the fourth aspect, the present application provides an elastic wave filter, which includes a dual-mode surface acoustic wave filter. The dual-mode surface acoustic wave filter includes a plurality of transducers arranged laterally, the transducers include a first transducer, a second transducer, a third transducer, a fourth transducer and a fifth transducer, and a third reflection grid group respectively arranged on the outside of the first transducer and the fifth transducer, the third reflection grid group is a suspended short-circuit reflection grid and is not connected to the ground end; the first transducer, the third transducer and the fifth transducer are connected to the signal input end; the second transducer and the fourth transducer are connected to the signal output end; the first transducer and the second transducer are connected with SG polarity, and the second transducer and the third transducer are connected with GS polarity; the third transducer and the fourth transducer are connected with SG polarity, and the fourth transducer and the fifth transducer are connected with GS polarity.

[0016] Furthermore, the number of electrode fingers of the interdigital transducer is greater than or equal to 5, and the number of electrode fingers is an odd number.

[0017] In a fifth aspect, the present application provides an electronic communication device, which includes the elastic wave filter according to the fourth aspect.

[0018] As can be seen from the above technical solutions, the advantages and positive effects of the elastic wave filter, duplexer circuit, and electronic communication device proposed in this application are:

[0019] This application aims to effectively broaden the filter's bandwidth by carefully designing the polarity configuration between the IDTs in a dual-mode surface acoustic wave (SAW) filter, as well as the polarity relationship between the IDTs and the reflector. Based on the same inventive concept, an elastic wave filter with significantly improved bandwidth is proposed. This filter is further applied to electronic communication devices to achieve even greater bandwidth and meet growing performance requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above content of this application and the following specific embodiments will be better understood when read in conjunction with the accompanying drawings. It should be noted that the accompanying drawings are only examples of the technical solutions claimed.

[0021] Figure 1 is a partial structural diagram of an elastic wave filter including a DMS according to a first embodiment of the present application;

[0022] Figure 2 is a partial structural diagram of the elastic wave filter including DMS of Comparative Example 1;

[0023] Figure 3 is a partial structural diagram of the elastic wave filter including DMS of Comparative Example 2;

[0024] Figure 4 is a performance comparison diagram of the elastic wave filter including the DMS structure of the first embodiment and the elastic wave filters including the DMS structures of comparative examples 1 and 2;

[0025] Figure 5 is a partial structural diagram of a DMS included in the elastic wave filter according to the second embodiment of the present application;

[0026] Figure 6 is a partial structural diagram of the elastic wave filter including DMS according to Comparative Example 3 of the present application;

[0027] Figure 7 is a performance comparison diagram of an elastic wave filter including a DMS structure of the second embodiment and an elastic wave filter including a 3DMS structure of a comparative example;

[0028] Figure 8 is a schematic diagram of a duplexer circuit of the present application.

[0029] The description of the accompanying drawings is as follows:

[0030] Elastic wave filter: 1;

[0031] a first dual-mode surface acoustic wave filter 10;

[0032] First interdigital transducer: 11;

[0033] Second interdigital transducer: 12;

[0034] Third interdigital transducer: 13;

[0035] Fourth interdigital transducer: 14;

[0036] Fifth interdigital transducer: 15;

[0037] Sixth interdigital transducer: 16;

[0038] First reflector group: 17;

[0039] Second reflector group: 18;

[0040] The third reflector group: 19, 19`;

[0041] a second dual-mode surface acoustic wave filter 20;

[0042] Signal input terminal: 21, 21`;

[0043] Ground terminal: 22;

[0044] Signal output terminal: 23;

[0045] First signal output terminal: 24;

[0046] Second signal output terminal: 25;

[0047] First electrode fingers: 31, 31`, 31``;

[0048] Second electrode fingers: 32, 32`, 32``;

[0049] The third electrode fingers: 33, 33`, 33``;

[0050] Fourth electrode fingers: 34, 34`, 34``;

[0051] Fifth electrode fingers: 35, 35`, 35``;

[0052] Sixth electrode fingers: 36, 36`, 36``;

[0053] Seventh electrode fingers: 37, 37`, 37``;

[0054] The eighth electrode fingers are: 38, 38`, 38``. DETAILED DESCRIPTION

[0055] The detailed features and advantages of the present application are described in detail below in the specific implementation methods, and the content is sufficient to enable any technical personnel in this field to understand the technical content of the present application and implement it accordingly. Based on the description, claims and drawings disclosed in this specification, technical personnel in this field can easily understand the relevant purposes and advantages of the present application.

[0056] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0057] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product is usually placed when in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0058] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0059] For the convenience of explanation, in this application, the “signal terminal” mentioned specifically refers to all connection ports except the ground terminal, including ports connected to the signal input terminal, the signal output terminal and the interdigital transducer.

[0060] First embodiment

[0061] Please refer to Figure 1 As shown, in the first embodiment provided by the present application, the elastic wave filter 1 includes a first dual-mode surface acoustic wave filter 10 and a second dual-mode surface acoustic wave filter 20 .

[0062] The first dual-mode surface acoustic wave filter 10 and the second dual-mode surface acoustic wave filter 20 respectively include a plurality of reflection gratings and a plurality of interdigital transducers. The reflection gratings are arranged on both sides of the interdigital transducers.

[0063] The IDT includes multiple electrode fingers arranged horizontally and intersectingly, and multiple bus bars arranged vertically opposite each other. The electrode fingers are connected to the bus bars and extend vertically. The number of electrode fingers in the IDT is greater than or equal to 5, and the number of electrode fingers is an odd number.

[0064] Specifically, the first dual-mode surface acoustic wave filter 10 includes a first IDT 11 , a second IDT 12 , and a third IDT 13 arranged laterally, and a first reflection grating group 17 disposed outside the first IDT 11 and the third IDT 13 .

[0065] The first IDT 11 and the second IDT 12 are connected with SG polarity, and the second IDT 12 and the third IDT 13 are connected with GS polarity.

[0066] The second dual-mode surface acoustic wave filter 20 includes a fourth IDT 14 , a fifth IDT 15 and a sixth IDT 16 arranged laterally, and a second reflection grating group 18 disposed outside the fourth IDT 14 and the sixth IDT 16 .

[0067] The fourth IDT 14 and the fifth IDT 15 are connected with SG polarity, and the fifth IDT 15 and the sixth IDT 16 are connected with GS polarity.

[0068] One end of the first IDT 11 , the second IDT 12 , the third IDT 13 , the fourth IDT 14 , the fifth IDT 15 and the sixth IDT 16 is connected to the ground terminal 22 .

[0069] The other end of the second IDT 12 is connected to the signal input terminal 21, the other end of the first IDT 11 is connected to the other end of the fourth IDT 14, the other end of the third IDT 13 is connected to the other end of the sixth IDT 16, and the other end of the fourth IDT 14 is connected to the signal output terminal 23.

[0070] As can be understood, the DMS (dual-mode surface acoustic wave) components of the elastic wave filter 1 of the present invention are arranged as follows: from left to right, a reflector grating, multiple interdigital transducers, and a transmitter grating. These components are strategically arranged parallel to the direction of acoustic wave propagation or at an angle of less than 15°. Crucially, all elastic wave components involved in acoustic wave transmission and processing are mounted on a piezoelectric crystal substrate to ensure efficient filter operation and optimized performance.

[0071] In the first embodiment of the present application, the elastic wave filter 1 includes two DMS elements connected in series, each DMS contains three interdigital transducers, the middle interdigital transducer of the first DMS element is the signal input end, the transducers on both sides are the signal output ends, and the output ends are connected to the interdigital transducers on both sides of the second DMS element. After the propagation of sound waves and the conversion of piezoelectric effect, the middle interdigital transducer of the second DMS element outputs the signal.

[0072] In the first DMS element, the interdigital transducers at the outermost ends of the middle transducer are electrically grounded through a bus bar, and the interdigital transducers at the outermost ends of each of the two sides are connected to the electrical signal through a bus bar. Thus, the three interdigital transducers of the first DMS element form an SG-GS polarity connection mode.

[0073] Similarly, the three IDTs of the second DMS element form a SG-GS polarity connection. In addition, the end fingers of the IDTs near the reflector in both DMS elements are connected to the electrical signal.

[0074] Specifically, the first electrode finger 31 of the first IDT 11, which is close to the second IDT 12, is connected to the fourth IDT 14. The second electrode finger 32 of the second IDT 12, which is close to the first IDT 11, is connected to the ground terminal 22. The third electrode finger 33 of the second IDT 12, which is close to the third IDT 13, is connected to the ground terminal 22. The fourth electrode finger 34 of the third IDT 13, which is close to the second IDT 12, is connected to the sixth IDT 16. It can be understood that this connection arrangement of the electrode finger elements enables the first dual-mode surface acoustic wave filter 10 to form an SG-GS polarity connection.

[0075] The fifth electrode finger 35 of the fourth IDT 14, which is adjacent to the fifth IDT 15, is connected to the first IDT 11. The sixth electrode finger 36 of the fifth IDT 15, which is adjacent to the fourth IDT 14, is connected to the ground terminal 22. The seventh electrode finger 37 of the fifth IDT 15, which is adjacent to the sixth IDT 16, is connected to the ground terminal 22. The eighth electrode finger 38 of the sixth IDT 16, which is adjacent to the fifth IDT 15, is connected to the third IDT 13. It will be appreciated that this arrangement of electrode finger elements ensures that the second dual-mode SAW filter 20 has the same polarity as the first dual-mode SAW filter 10, forming an SG-GS connection.

[0076] As you can see, two DMS (dual-mode surface acoustic wave) elements connected in series together form the core of elastic wave filter 1. Each DMS element has three built-in interdigital transducers, with reflective gratings cleverly arranged on the outside of these transducers. These reflective gratings are connected to the ground signal in the layout through a carefully designed wiring scheme, ensuring stable signal transmission and processing.

[0077] The IDT consists of two comb-like electrode fingers that intertwine and mesh tightly together, with one end of each electrode finger connected to a bus bar. These bus bars are responsible for the input, output, or grounding of electrical signals, providing flexible and reliable signal connections for the entire filter.

[0078] The polarity between the IDTs is designed to be SG-GS, or signal-ground-signal-ground. In particular, the electrode fingers closest to the reflector are cleverly connected to the busbars carrying the input or output electrical signals. This layout optimizes signal transmission efficiency.

[0079] It is worth noting that in this application, the first, second, third, fourth, fifth, and sixth IDTs have the same number of electrode fingers. The odd number of IDTs in each DMS element not only enhances the symmetry of the structure but also helps improve filter performance.

[0080] In addition, the number of electrode fingers of the first IDT, the second IDT, the third IDT, the fourth IDT, the fifth IDT and the sixth IDT may also be different, and the embodiments of the present application are not limited thereto.

[0081] Each IDT is cleverly divided into multiple zones along the longitudinal direction. These zones can vary in metallization, or the wavelengths of each zone can be set to different values. Those skilled in the art can select design strategies based on specific application scenarios, providing greater flexibility and customizability for the filter, enabling more refined and efficient signal processing.

[0082] To further illustrate the passband performance of the elastic wave filter 1 of the first embodiment, please refer to the following comparative examples 1 and 2.

[0083] Comparative Example 1

[0084] Please refer to Figure 2 The differences between Comparative Example 1 and the first embodiment are as follows:

[0085] The first electrode finger 31 ′ of the first IDT close to the second IDT is connected to the ground terminal 22 , and the second electrode finger 32 ′ of the second IDT close to the first IDT is connected to the signal terminal.

[0086] The third electrode finger 33 ′ of the second IDT close to the third IDT is connected to the signal terminal, and the fourth electrode finger 34 ′ of the third IDT close to the second IDT is connected to the ground terminal 22 .

[0087] That is, the first dual-mode surface acoustic wave filter forms a GS-SG polarity connection.

[0088] The fifth electrode finger 35 ′ of the fourth IDT close to the fifth IDT is connected to the ground terminal 22 , and the sixth electrode finger 36 ′ of the fifth IDT close to the fourth IDT is connected to the signal terminal.

[0089] The seventh electrode finger 37 ′ of the fifth IDT close to the sixth IDT is connected to the signal terminal, and the eighth electrode finger 38 ′ of the sixth IDT close to the fifth IDT is connected to the ground terminal 22 .

[0090] That is, the second dual-mode surface acoustic wave filter forms a GS-SG polar connection.

[0091] In comparative example 1, the polarities of the interdigital transducers of the two DMS elements are both set to GS-SG. Apart from this, the other settings are the same as those of the first embodiment.

[0092] Comparative Example 2

[0093] Please refer to Figure 3 The differences between Comparative Example 2 and the first embodiment are as follows:

[0094] The first electrode finger 31 ″ of the first IDT close to the second IDT is connected to the ground terminal 22 , and the second electrode finger 32 ″ of the second IDT close to the first IDT is connected to the signal terminal.

[0095] The third electrode finger 33 ″ of the second IDT close to the third IDT is connected to the signal terminal, and the fourth electrode finger 34 ″ of the third IDT close to the second IDT is connected to the ground terminal 22 .

[0096] That is, the first dual-mode surface acoustic wave filter forms a GS-SG polarity connection.

[0097] The fifth electrode finger 35 ″ of the fourth IDT close to the fifth IDT is connected to the signal terminal, and the sixth electrode finger 36 ″ of the fifth IDT close to the fourth IDT is connected to the ground terminal 22 .

[0098] The seventh electrode finger 37 ″ of the fifth IDT close to the sixth IDT is connected to the ground terminal 22 , and the eighth electrode finger 38 ″ of the sixth IDT close to the fourth IDT is connected to the signal terminal.

[0099] That is, the second dual-mode surface acoustic wave filter forms a polarity connection of SG-GS.

[0100] In comparative example 2, the polarity between the IDTs of the first DMS element is set to GS-SG, and the polarity between the IDTs of the second DMS element is set to SG-GS. Other than that, the other settings are the same as those of the first embodiment.

[0101] Please refer to Figure 4 , Figure 4 This is a comparison result of the passband electrical performance of the first embodiment and comparative examples 1 and 2.

[0102] In the first embodiment, when the polarities between the interdigital transducers of the two serially connected DMS elements are both SG-GS polarities, the bandwidth of the passband is the maximum.

[0103] In Comparative Example 1, when the polarities between the IDTs of the two serially connected DMS elements are both GS-SG, the bandwidth of the passband is the smallest.

[0104] In comparative example 2, when the IDT of one DMS element has GS-SG polarity and the IDT of the other DMS element has SG-GS polarity, the bandwidth of the passband is between that of the first embodiment and comparative example 1.

[0105] Please refer to Figure 5 Based on the same inventive concept, the present application also provides a duplexer circuit, which includes: a signal input terminal 21', a first signal output terminal 24 and a second signal output terminal 25, a first filter circuit is arranged between the signal input terminal 21' and the first signal output terminal 24, and a second filter circuit is arranged between the signal input terminal 21' and the second signal output terminal 25, and the first filter circuit and the second filter circuit are connected in parallel.

[0106] The elastic wave filter 1 of the present application is provided in the first filter circuit and / or the second filter circuit.

[0107] Second embodiment

[0108] Please refer to Figure 6 As shown, in the second embodiment provided by the present application, the present application also provides another elastic wave filter. The elastic wave filter includes a dual-mode surface acoustic wave filter, which includes a plurality of interdigital transducers arranged laterally, the interdigital transducers including a first interdigital transducer 11, a second interdigital transducer 12, a third interdigital transducer 13, a fourth interdigital transducer 14, and a fifth interdigital transducer 15, and a third reflective grid group 19 respectively disposed outside the first interdigital transducer 11 and the fifth interdigital transducer 15, the third reflective grid group 19 being a suspended short-circuit reflective grid and not connected to the ground terminal 22.

[0109] Specifically, the first IDT 11 , the third IDT 13 and the fifth IDT 15 are connected to the signal input end; the second IDT 12 and the fourth IDT 14 are connected to the signal output end.

[0110] The first IDT 11 and the second IDT 12 are connected with SG polarity, and the second IDT 12 and the third IDT 13 are connected with GS polarity.

[0111] The third IDT 13 and the fourth IDT 14 are connected with SG polarity, and the fourth IDT 14 and the fifth IDT 15 are connected with GS polarity.

[0112] As will be appreciated, in the second embodiment, the DMS element is equipped with five IDTs. These IDTs all have an odd number of fingers, a design that not only enhances structural symmetry but also helps optimize filtering performance. Each IDT is divided into multiple regions in the longitudinal direction, each of which can be configured with a different metallization or wavelength. The entire DMS element is symmetrical about the central IDT.

[0113] The first IDT, the second IDT, the third IDT, the fourth IDT, the fifth IDT and the sixth IDT have the same number of electrode fingers.

[0114] The IDTs are cleverly arranged in a SG-GS-SG-GS configuration (signal-ground-signal-ground-signal). This polarity configuration helps optimize signal transmission and processing efficiency. In particular, the electrode fingers of the IDTs adjacent to the reflector are connected to the input electrical signal via bus bars. This layout ensures efficient signal entry and processing within the DMS element.

[0115] Unlike the first embodiment, in the second embodiment, the third reflectors 19 on both sides of the DMS of the elastic wave filter are not connected to the ground terminal 22. Specifically, the third reflectors 19 on both sides of the DMS are configured as suspended short-circuit reflectors, which are electrically disconnected from the ground. This further increases the passband bandwidth of the elastic wave filter.

[0116] To further illustrate the passband performance of the elastic wave filter of the second embodiment, please refer to the following comparative example 3.

[0117] Comparative Example 3

[0118] Please refer to Figure 7 , which is different from the second embodiment of the present application, is that the third reflection gratings 19 ′ on both sides of the elastic wave filter in comparative example 3 are connected to the ground terminal 22 .

[0119] Except for this, all configurations of the DMS element are the same as those of the elastic wave filter of the second embodiment.

[0120] Please refer to Figure 8 , Figure 8 This is a comparison result of the passband electrical performance between the second embodiment and comparative example 3.

[0121] As can be understood, in the elastic wave filter design of this application, the polarity configuration between the interdigital transducers of the DMS element is innovatively set to SG-GS-SG-GS, i.e., an alternating arrangement of signal-ground-signal-ground-signal. Particularly unique is that because the third reflector is not connected to the ground terminal, the polarity of the electrode fingers adjacent to the reflector is set to signal (S).

[0122] This careful polarization configuration, combined with the reflector design, significantly improves the filter's passband performance. Specifically, it helps optimize the signal transmission path, reduces signal losses during propagation, and enhances the filter's ability to filter signals within a specific frequency range. Consequently, this design not only improves the filter's frequency selectivity but also ensures greater stability and clarity for signals within the passband.

[0123] It should be noted that the configuration in the second embodiment where the reflection grid is not connected to the ground terminal can also be applied to the first embodiment to further increase the passband bandwidth performance of the elastic wave filter of the first embodiment.

[0124] Based on the same inventive concept, the present application also provides an electronic communication device, which includes the elastic wave filter provided by the first embodiment and / or the second embodiment of the present application.

[0125] It can be understood that electronic communication equipment covers elastic wave sensors and elastic wave filters equipped with interdigital transducers, as well as components such as duplexers and multiplexers constructed using these filters.

[0126] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0127] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0128] The terms and expressions used herein are for descriptive purposes only, and this application is not intended to be limited to these terms and expressions. The use of these terms and expressions does not exclude any equivalent features of the features illustrated and described (or portions thereof), and it should be recognized that various modifications that may exist are also intended to be included within the scope of the claims. Other modifications, variations, and substitutions are also possible. Accordingly, the claims should be deemed to cover all such equivalents.

[0129] Similarly, it should be pointed out that although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should realize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions can be made without departing from the spirit of the invention. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. An elastic wave filter, comprising a first dual-mode surface acoustic wave filter and a second dual-mode surface acoustic wave filter, characterized in that: The first dual-mode surface acoustic wave filter includes a first interdigital transducer, a second interdigital transducer, and a third interdigital transducer arranged laterally, and a first reflection grating group respectively arranged on the outside of the first interdigital transducer and the third interdigital transducer, the first interdigital transducer and the second interdigital transducer are connected with SG polarity, and the second interdigital transducer and the third interdigital transducer are connected with GS polarity; The second dual-mode surface acoustic wave filter includes a fourth interdigital transducer, a fifth interdigital transducer, and a sixth interdigital transducer arranged laterally, and a second reflection grating group arranged outside the fourth interdigital transducer and the sixth interdigital transducer, respectively, the fourth interdigital transducer and the fifth interdigital transducer are connected with SG polarity, and the fifth interdigital transducer and the sixth interdigital transducer are connected with GS polarity; One end of the first IDT, the second IDT, the third IDT, the fourth IDT, the fifth IDT and the sixth IDT is connected to a ground terminal; The other end of the second interdigital transducer is connected to the signal input end, the other end of the first interdigital transducer is connected to the other end of the fourth interdigital transducer, the other end of the third interdigital transducer is connected to the other end of the sixth interdigital transducer, and the other end of the fourth interdigital transducer is connected to the signal output end.

2. The elastic wave filter according to claim 1, wherein The first reflection grid group and the second reflection grid group are not connected to the ground end.

3. The elastic wave filter according to claim 1, wherein The first electrode finger of the first IDT close to the second IDT is connected to the fourth IDT, and the second electrode finger of the second IDT close to the first IDT is connected to the ground end; The third electrode finger of the second IDT close to the third IDT is connected to the ground terminal, and the fourth electrode finger of the third IDT close to the second IDT is connected to the sixth IDT; The fifth electrode finger of the fourth IDT close to the fifth IDT is connected to the first IDT, and the sixth electrode finger of the fifth IDT close to the fourth IDT is connected to the ground end; The seventh electrode finger of the fifth IDT close to the sixth IDT is connected to the ground end, and the eighth electrode finger of the sixth IDT close to the fifth IDT is connected to the third IDT.

4. The elastic wave filter according to claim 1, wherein The number of electrode fingers of the first IDT, the second IDT, the third IDT, the fourth IDT, the fifth IDT or the sixth IDT is greater than or equal to 5, and the number of electrode fingers is an odd number.

5. The elastic wave filter according to claim 1, wherein The first IDT, the second IDT, the third IDT, the fourth IDT, the fifth IDT and the sixth IDT have the same number of electrode fingers.

6. A duplexer circuit, comprising: A signal input terminal, a first signal output terminal, and a second signal output terminal, wherein a first filter circuit is provided between the signal input terminal and the first signal output terminal, and a second filter circuit is provided between the signal input terminal and the second signal output terminal, and the first filter circuit and the second filter circuit are connected in parallel, characterized in that: The first filter circuit and / or the second filter circuit includes the elastic wave filter according to claim 1 .

7. An electronic communication device, characterized in that: The electronic communication device includes the elastic wave filter according to claim 1.

8. An elastic wave filter, characterized in that: The elastic wave filter comprises a dual-mode surface acoustic wave filter, the dual-mode surface acoustic wave filter comprises a plurality of interdigital transducers arranged laterally, the interdigital transducers comprising a first interdigital transducer, a second interdigital transducer, a third interdigital transducer, a fourth interdigital transducer and a fifth interdigital transducer, and a third reflective grid group respectively arranged on the outside of the first interdigital transducer and the fifth interdigital transducer, the third reflective grid group being a suspended short-circuit reflective grid and not connected to a ground terminal; The first IDT, the third IDT and the fifth IDT are connected to the signal input terminal; the second IDT and the fourth IDT are connected to the signal output terminal; The first IDT and the second IDT are connected with SG polarity, and the second IDT and the third IDT are connected with GS polarity; The third IDT and the fourth IDT are connected with SG polarity, and the fourth IDT and the fifth IDT are connected with GS polarity.

9. The elastic wave filter according to claim 8, wherein The number of electrode fingers of the interdigital transducer is greater than or equal to 5, and the number of electrode fingers is an odd number.

10. An electronic communication device, characterized in that: The electronic communication device includes the elastic wave filter according to claim 8.

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