Filter device and radio frequency front-end module

Abstract

The utility model discloses a filter device and a radio frequency front end module, the filter device comprises a chip and at least three filters integrated on the chip, and the occupied area can be reduced while the use requirements of at least three frequency bands can be met. The at least three filters comprise a first filter, a second filter and a third filter, and the third filter is located between the first filter and the second filter. The first filter includes a first longitudinally coupled acoustic resonator including a plurality of interdigital transducers. The second filter includes a second longitudinally coupled acoustic resonator including a plurality of interdigital transducers. The third filter comprises a trapezoidal circuit, and the trapezoidal circuit comprises at least two series arm resonators and at least two parallel arm resonators and can be matched with other filters for flexible layout, so that the overall occupied area of the plurality of filters is reduced, and the miniaturization of the filter device is realized while the performance is maintained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radio frequency filtering, in particular to a filter device and a radio frequency front-end module. BACKGROUND

[0002] In the prior art, multiple filters are usually separately laid out and manufactured on different chips, and then integrated together in the later substrate packaging stage. However, this packaging method has high production cost and large product size, which is not conducive to the miniaturization and integration design of the product.

[0003] Therefore, how to reduce the size of the filter device while ensuring performance has become a problem to be solved. CONTENT OF THE INVENTION

[0004] Therefore, the present application provides a filter device and a radio frequency front-end module.

[0005] The first aspect of the present application provides a filter device, comprising:

[0006] a chip;

[0007] at least three filters integrated on the chip, the at least three filters comprising a first filter, a second filter and a third filter, the third filter being located between the first filter and the second filter;

[0008] the first filter comprising a first longitudinally coupled acoustic wave resonator, the first longitudinally coupled acoustic wave resonator comprising a plurality of interdigital transducers;

[0009] the second filter comprising a second longitudinally coupled acoustic wave resonator, the second longitudinally coupled acoustic wave resonator comprising a plurality of interdigital transducers;

[0010] the third filter comprising a ladder circuit, the ladder circuit comprising at least two series arm resonators and at least two parallel arm resonators.

[0011] The second aspect of the present application provides a radio frequency front-end module, comprising the above filter device.

[0012] As can be seen from the above technical solution, the filter device provided by the present application integrates at least three filters on the same chip, which can meet the use requirements of at least three frequency bands while reducing the occupied area. The first filter and the second filter comprise longitudinally coupled acoustic wave resonators, which can reduce the occupied area while achieving the required performance compared to using conventional resonators. The third filter adopts a ladder circuit, which can be flexibly arranged with other filters, has a compact structure and reduces the layout area, thereby reducing the overall occupied area of multiple filters, achieving miniaturization design of the filter device while maintaining performance. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0014] Fig. 1 This is a schematic diagram of the circuit architecture of the filter device proposed in the embodiments of this application;

[0015] Fig. 2 This is a schematic diagram of the filter device proposed in the embodiments of this application. The areas where the first filter, second filter, third filter and fourth filter are located are shown by boxes in the figure.

[0016] Explanation of reference numerals in the attached figures:

[0017] 100. Filter device; 10. Chip; 11. First region; 12. Second region; 20. First filter; 21. First longitudinally coupled acoustic resonator; 22. First input terminal; 23. First output terminal; 24. First ground terminal; 25. First inductor; 26. First resonator; 30. Second filter; 31. Second longitudinally coupled acoustic resonator; 32. Second input terminal; 33. Second output terminal; 34. Second ground terminal; 35. Third inductor; 40. Third filter; 41. Ladder circuit; 42. Third input terminal; 43. Third output terminal; 44. Third ground terminal; 45. Fourth inductor; 50. Fourth filter; 51. Third longitudinally coupled acoustic resonator; 52. Fourth input terminal; 53. Fourth output terminal; 54. Fourth ground terminal; 55. Second inductor; 60. Resonant group. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] It should be understood that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0020] It should also be understood that when an element is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements can be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements can be present.

[0021] The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting thereof. As used in this description and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be understood that the terms "comprising," "including," "containing," and "having," are inclusive and do not exclude other

[0022] It should also be further understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative ("or").

[0023] Reference will now be made to Figs. 1-2 The embodiments of the present application provide a filter device 100, which comprises a chip 10 and at least three filters integrated on the chip 10. The at least three filters comprise a first filter 20, a second filter 30 and a third filter 40. The third filter 40 is located between the first filter 20 and the second filter 30. The first filter 20 comprises a first longitudinally-coupled acoustic resonator 21, which comprises a plurality of interdigital transducers. The second filter 30 comprises a second longitudinally-coupled acoustic resonator 31, which comprises a plurality of interdigital transducers. The third filter 40 comprises a ladder circuit 41, which comprises at least two series arm resonators and at least two parallel arm resonators.

[0024] It can be understood that the plurality means at least two, i.e., the first longitudinally-coupled acoustic resonator 21 and the second longitudinally-coupled acoustic resonator 31 can comprise two, three or even more interdigital transducers.

[0025] The filter device 100 provided by the embodiments of the present application integrates at least three filters on the same chip 10, which can meet the use requirements of at least three frequency bands and reduce the occupied area. The first filter 20 and the second filter 30 comprise longitudinally-coupled acoustic resonators, which can reduce the occupied area while achieving the required performance compared with conventional resonators. The third filter 40 adopts the ladder circuit 41, which can be flexibly arranged with other filters, has a compact structure and reduces the arrangement area, thereby reducing the overall occupied area of the plurality of filters, maintaining the performance and realizing the miniaturized design of the filter device 100.

[0026] Exemplarily, the first longitudinal coupled acoustic wave resonator 21 and the second longitudinal coupled acoustic wave resonator 31 can be longitudinal coupled acoustic wave resonators or other resonators with multiple interdigital transducers, which are also known as dual-mode surface acoustic wave resonators, and are capable of supporting two operating modes (or two resonant modes) at the same time. In the related art, if longitudinal coupled acoustic wave resonators are not used, more conventional resonators (i.e., resonators with only one resonant mode) need to be used to achieve the same performance. Therefore, by using longitudinal coupled acoustic wave resonators, the first filter 20 and the second filter 30 in the embodiment can achieve the required performance while reducing the occupied area.

[0027] In optional embodiments, there can be at least three filters, which can be three filters, or four, five or even more filters. Among them, the first filter 20, the second filter 30 and the third filter 40 can be any three filters of the at least three filters, as long as the third filter 40 provided with the ladder circuit 41 is located between the first filter 20 and the second filter 30 provided with longitudinal coupled acoustic wave resonators, that is, the first filter 20 and the third filter 40 can be adjacent or not adjacent, and in the case of not adjacent, there can be other filters or other components between the first filter 20 and the third filter 40. Understandably, the second filter 30 and the third filter 40 can be adjacent or not adjacent, and in the case of not adjacent, there can be other filters or other components between the second filter 30 and the third filter 40.

[0028] In some embodiments, among the at least three filters, the bandwidth of the third filter 40 is smaller than that of any other filter. That is, among all the filters, the bandwidth of the third filter 40 is the smallest. Among them, the bandwidth of the filter refers to the frequency range that the filter can pass, which is usually represented as the difference between two cutoff frequencies. The two cutoff frequencies are the lower limit frequency and the upper limit frequency of the filter, which define the passband range of the filter. Therefore, the third filter 40 with the smallest bandwidth is provided with the ladder circuit 41 to achieve flexible layout, so that the occupied area of the multiple filters as a whole can be reduced without reducing the performance of the filters, and the miniaturization design of the filter device 100 can be achieved.

[0029] Please refer to Fig. 2In some embodiments, the chip 10 has a first region 11 and a second region 12 arranged along a first direction on the surface of the chip 10, and at least three filters are arranged in the first region 11 and the second region 12. The filters arranged in the first region 11 have a higher frequency band than the filters arranged in the second region 12. In this way, the filters with a relatively high frequency band are arranged in the same region, and the filters with a relatively low frequency band are arranged in the same region, which is easier to implement in the process and reduces the processing cost.

[0030] For example, the first direction can be the length direction of the chip 10, as shown in FIG. 1. Fig. 2 As shown in FIG. 1, the first region 11 can be the left region of the surface of the chip 10, and the second region 12 can be the right region of the surface of the chip 10. The filters arranged in the first region 11 can be defined as high-frequency filters, and the filters arranged in the second region 12 can be defined as medium-frequency filters. Arranging the high-frequency filters in the same region and arranging the medium-frequency filters in the same region is easier to implement in the process and reduces the processing cost. Of course, in other examples, the first region 11 can also be the right region of the surface of the chip 10, and the second region 12 can also be the left region of the surface of the chip 10. The specific range of the first region 11 and the second region 12 is not limited. The region where each high-frequency filter is located is the first region 11, and the region where each medium-frequency filter is located is the second region 12.

[0031] In some embodiments, the frequency band of the filters arranged in the first region 11 is greater than the frequency band of the filters arranged in the second region 12.

[0032] In some embodiments, the frequency band of the filters arranged in the first region 11 ranges from greater than 2200 MHz to less than or equal to 3000 MHz. The frequency band of the filters arranged in the second region 12 ranges from greater than or equal to 1000 MHz to less than or equal to 2200 MHz. That is, the frequency band of the high-frequency filter ranges from 2200 MHz to 3000 MHz (not including 2200 MHz), and the frequency band of the medium-frequency filter ranges from 1000 MHz to 2200 MHz (including 2200 MHz). The frequency bands of the filters are all different, so that the use demand of multiple frequency bands can be met.

[0033] In some embodiments, each of the at least three filters includes an input terminal, an output terminal and a ground terminal, and the two adjacent filters in the first region 11 are provided with inductors, and a ground structure is arranged between the inductors of the two filters. Since the two high-frequency filters have higher sensitivity to coupling, the ground structure is arranged between the inductors of the two high-frequency filters to form an isolation, thereby preventing crosstalk of the parallel inductors of the two high-frequency filters. Exemplarily, the inductors of the filters can be parallel inductors connected to the input terminals, or inductors at other positions.

[0034] Referring to Figs. 1-2 In some embodiments, among the two adjacent filters in the first region 11, one of the filters is connected with a first inductor 25 between the input terminal and the ground terminal, and the other filter is connected with a second inductor 55 between the input terminal and the ground terminal; and a ground structure is arranged between the first inductor 25 and the second inductor 55. Since the input terminals of the two adjacent filters are arranged close to each other, crosstalk between the first inductor 25 and the second inductor 55 is likely to occur, and therefore the ground structure is arranged between the first inductor 25 and the second inductor 55 to form an isolation, thereby preventing crosstalk of the parallel inductors of the input terminals of the two high-frequency filters. The inductors are connected in parallel between the input terminals and the ground terminals, which helps to filter out interference signals of specific frequencies and improve the performance of the filters.

[0035] Exemplarily, the chip 10 is arranged on a substrate, and the ground structure can be a ground metal arranged on the substrate. The ground metal is arranged on the substrate at a position corresponding to the first inductor 25 and the second inductor 55 to form an isolation, thereby preventing crosstalk of the parallel inductors of the input terminals of the two high-frequency filters.

[0036] In some embodiments, the first filter 20 can be a high-frequency filter, and the second filter 30 and the third filter 40 can be intermediate-frequency filters, i.e., the first filter 20 is arranged in the first region 11, and the second filter 30 and the third filter 40 are arranged in the second region 12. It can be understood that the first region 11 can also arrange more high-frequency filters, and the second region 12 can also arrange more intermediate-frequency filters.

[0037] In some embodiments, the first filter 20 further includes a first input terminal 22, a first output terminal 23 and a first ground terminal 24, and the first longitudinal-coupled acoustic wave resonator 21 is connected between the first input terminal 22 and the first output terminal 23. The first inductor 25 can be an inductor connected between the first input terminal 22 and the first ground terminal 24.

[0038] In some embodiments, the filter device 100 can further comprise a fourth filter 50 located in the first region 11, the fourth filter 50 comprising a third longitudinally-coupled acoustic wave resonator 51 comprising a plurality of interdigital transducers. The fourth filter 50 further comprises a fourth input terminal 52, a fourth output terminal 53 and a fourth ground terminal 54, the third longitudinally-coupled acoustic wave resonator 51 being connected between the fourth input terminal 52 and the fourth output terminal 53. The second inductor 55 can be an inductor connected between the fourth input terminal 52 and the fourth ground terminal 54.

[0039] In some embodiments, the second filter 30 further comprises a second input terminal 32, a second output terminal 33 and a second ground terminal 34, the second longitudinally-coupled acoustic wave resonator 31 being connected between the second input terminal 32 and the second output terminal 33. The third inductor 35 can be an inductor connected between the second input terminal 32 and the second ground terminal 34.

[0040] In some embodiments, the third filter 40 further comprises a third input terminal 42, a third output terminal 43 and a third ground terminal 44, the series arm resonators being connected in series between the third input terminal 42 and the third output terminal 43, the parallel arm resonators being connected at one end to the input or output of the series arm resonators and at the other end to the third ground terminal 44. The fourth inductor 45 can be an inductor connected between the third input terminal 42 and the third ground terminal 44.

[0041] Exemplarily, the number of series arm resonators is at least two, i.e. the third filter 40 can comprise two, three, four or more series arm resonators connected in series between the third input terminal 42 and the third output terminal 43. The number of parallel arm resonators is at least two, i.e. the third filter 40 can comprise two, three, four or more parallel arm resonators, the plurality of series arm resonators and the plurality of parallel arm resonators forming the ladder circuit 41 of the third filter 40.

[0042] In some embodiments, the first filter 20 is located in the first region 11, and the first filter 20 can realize carrier aggregation with any other filter. The carrier aggregation is also referred to as CA requirement, that is, the first filter 20 can have CA requirement with the second filter 30, the first filter 20 can also have CA requirement with the third filter 40, and when the filter device 100 further has a fourth filter 50 or even more filters, the first filter 20 can also have CA requirement with the fourth filter 50 or other filters. The carrier aggregation of the first filter 20 with any other filter can combine the output or input signals of the two filters to support a larger transmission bandwidth and a higher data rate.

[0043] In some embodiments, the first filter 20 further includes a first input terminal 22, a first output terminal 23, a first ground terminal 24, and a first resonator 26. One end of the first resonator 26 is connected to the input end or the output end of the first longitudinal coupling acoustic wave resonator 21, and the other end of the first resonator 26 is connected to the first ground terminal 24. An inductive wire is arranged between the first longitudinal coupling acoustic wave resonator 21 and the first resonator 26, and the width of the inductive wire is 5 μm-15 μm. In this way, the first resonator 26 of the first filter 20 connected in parallel to the ground is connected through a relatively thin inductive wire, so that the formed electric energy can improve the out-of-band suppression effect.

[0044] For example, the width of the inductive wire can be 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, or 15 μm.

[0045] In some use scenarios, such as the scenario in which the first filter 20 realizes carrier aggregation with other filters, in order to ensure that the first filter 20 can meet the performance requirements of independent operation, a smaller series-parallel resonator capacitance ratio (the series-parallel resonator capacitance ratio refers to the ratio of the parallel resonant capacitance value to the series resonant capacitance value) can be used to ensure the performance of the wide passband and low insertion loss of the first filter 20. When a smaller series-parallel resonator capacitance ratio is used, the near-end out-of-band suppression of the first filter 20 will be poor. In order to improve the out-of-band suppression of the low-frequency side of the passband near end of the first filter 20, a relatively thin inductive wire can be used to connect the first resonator 26 of the first filter 20 connected in parallel to the ground, so that the formed electric energy can improve the out-of-band suppression effect.

[0046] In some embodiments, the chip 10 has a first region 11 and a second region 12 arranged along a first direction. The first filter 20 is arranged on a side of the first region 11 away from the second region 12, and the second filter 30 is arranged on a side of the second region 12 away from the first region 11. Thus, when there is a CA requirement between the first filter 20 and the second filter 30, the first filter 20 and the second filter 30 can be arranged on two sides of the chip 10 in the first direction, i.e., as shown in Fig. 2 , the first filter 20 can be arranged on the leftmost side of the chip 10, and the second filter 30 can be arranged on the rightmost side of the chip 10, so that the input terminal of the first filter 20 is isolated from the input terminal of the second filter 30, thereby avoiding crosstalk.

[0047] For example, the first direction can be the length direction of the chip 10, as shown in Fig. 2 , the first region 11 can be the left region of the surface of the chip 10, and the second region 12 can be the right region of the surface of the chip 10. Of course, in other examples, the first region 11 can also be the right region of the surface of the chip 10, and the second region 12 can also be the left region of the surface of the chip 10.

[0048] In some embodiments, the first longitudinal-coupled acoustic resonator 21 and the second longitudinal-coupled acoustic resonator 31 are arranged in a staggered manner in the first direction, which is perpendicular to the aperture direction of the filter. Thus, by arranging the longitudinal-coupled acoustic resonators of different filters in a staggered manner, the situation that multiple longitudinal-coupled acoustic resonators are arranged side by side in the middle region of the chip 10 can be avoided, thereby reducing the layout area without reducing the performance of the filter.

[0049] It can be understood that when the filter device 100 further includes other filters having longitudinal-coupled acoustic resonators, the longitudinal-coupled acoustic resonators of each filter can also be arranged in a staggered manner. For example, in some embodiments, at least three filters further include a fourth filter 50, and the fourth filter 50 includes a third longitudinal-coupled acoustic resonator 51 including multiple interdigital transducers. The first longitudinal-coupled acoustic resonator 21, the second longitudinal-coupled acoustic resonator 31, and the third longitudinal-coupled acoustic resonator 51 are arranged in a staggered manner in the first direction, which is perpendicular to the aperture direction of the filter. Thus, by arranging the first longitudinal-coupled acoustic resonator 21, the second longitudinal-coupled acoustic resonator 31, and the third longitudinal-coupled acoustic resonator 51 in a staggered manner, the situation that multiple longitudinal-coupled acoustic resonators are arranged side by side in the middle region of the chip 10 can be avoided, thereby reducing the layout area without reducing the performance of the filter.

[0050] Please refer to Fig. 2In some embodiments, the fourth filter 50 is arranged adjacent to the first filter 20, and the center line R1 of the first longitudinally-coupled acoustic wave resonator 21 in the aperture direction is misaligned with the center line R2 of the third longitudinally-coupled acoustic wave resonator 51 in the aperture direction. In order to further miniaturize the filter device 100, the fourth filter 50 can be arranged adjacent to the first filter 20, and the longitudinally-coupled acoustic wave resonators of the two adjacent filters are misaligned so that the center lines of the longitudinally-coupled acoustic wave resonators of the two adjacent filters in the aperture direction are not in a straight line, thereby further preventing interference between the two filters.

[0051] It can be understood that when the filter device 100 further includes other two adjacent filters having longitudinally-coupled acoustic wave resonators, the center lines of the longitudinally-coupled acoustic wave resonators of the two adjacent filters in the aperture direction can also be misaligned.

[0052] In some embodiments, the fourth filter 50 is located in the first region 11, the second filter 30 and the third filter 40 are located in the second region 12, and the third filter 40 is located between the fourth filter 50 and the second filter 30. In this way, the first filter 20 and the fourth filter 50 having high frequencies are arranged in the first region 11, the second filter 30 and the third filter 40 having medium frequencies are arranged in the second region 12, and the third filter 40 provided with the ladder circuit 41 is arranged between the fourth filter 50 and the second filter 30, thereby making the overall arrangement of the filter device 100 more flexible and facilitating reduction of the layout area.

[0053] In some embodiments, each of the at least three filters includes an input terminal, an output terminal, a ground terminal, and at least one resonance group 60 connected between the input terminal and the output terminal, and each resonance group 60 includes at least one resonator. Each resonance group 60 can include one, two, or even more resonators. For example, each filter can be provided with a resonator connected between the input terminal and the output terminal, a resonator connected between the input terminal and the ground terminal, and a resonator connected between the output terminal and the ground terminal. Here, the resonator refers to a conventional resonator, and the number of conventional resonators included in each filter is not limited herein and can be as required to achieve the desired performance.

[0054] In some embodiments, each resonator includes an interdigital transducer including two oppositely arranged bus bars and a plurality of electrode fingers connected between the two bus bars, and a reflector arranged on both sides of the interdigital transducer. Each filter further includes a piezoelectric substrate on which an input terminal, an output terminal and a ground terminal of the filter are arranged, and the interdigital transducer and the reflector of each resonator can be arranged on the same piezoelectric substrate. The piezoelectric substrate has a piezoelectric effect, i.e. generates an electric charge distribution and mechanical deformation when an electric field or mechanical stress is applied. The interdigital transducer, as an important component of the resonator, functions to complete the conversion of electric energy and mechanical energy, i.e. to generate and detect surface acoustic waves. The structure of the interdigital transducer is usually manufactured on the piezoelectric substrate by using a photolithography-coating-lift-off or coating-photolithography-etching process, or by other process methods. When a voltage signal is applied to the piezoelectric substrate, the interdigital transducer excites acoustic waves in the piezoelectric material. The changing voltage causes the piezoelectric substrate to deform, thereby exciting surface acoustic waves, and generating and propagating surface acoustic waves on the surface of the piezoelectric substrate by using the piezoelectric effect, so as to achieve signal processing and transmission.

[0055] In some use scenarios, if there is a potential difference between the adjacent reflectors of any two adjacent resonators in the filter device 100 (for example, one is connected to a signal, and the other is connected to a ground or not connected, which will cause a potential difference), it is possible to cause the generation of parasitic capacitance, thereby affecting the filter passband. The two adjacent resonators can be two adjacent resonators of the same filter, or two adjacent resonators of different filters.

[0056] In some use scenarios, the reflector can effectively reflect the acoustic waves between fr (lower limit frequency) and fa (upper limit frequency), and the acoustic waves beyond this range can leak out of the reflector. This leaked acoustic wave can be absorbed by the adjacent other resonator, thereby affecting the passband performance or out-of-band suppression performance of other frequency bands.

[0057] Therefore, in order to solve the above problems, the distance between the adjacent reflectors of the two adjacent resonators can be increased.

[0058] In some embodiments, the distance between the adjacent reflectors of the two adjacent resonators of the same filter is greater than 3 μm. Therefore, the generation of parasitic capacitance can be reduced, thereby reducing the influence on the filter passband. At the same time, by increasing the distance, the acoustic waves leaked from one of the reflectors can be avoided from being absorbed by the adjacent other reflector, thereby avoiding affecting the passband performance or out-of-band suppression performance of other frequency bands. Exemplarily, the distance between the adjacent reflectors of the two adjacent resonators of the same filter can be greater than 3 μm, greater than 4 μm, greater than 5 μm, or greater than 6 μm, etc.

[0059] In some embodiments, it can be further defined that the distance between the adjacent reflective gratings of the adjacent two resonators of the same filter is greater than 5 μm, so that the generation of parasitic capacitance can be better reduced, thereby reducing the influence on the passband of the filter, and at the same time, by increasing the distance, the sound waves leaked by one of the reflective gratings can be avoided from being absorbed by the adjacent other reflective grating as much as possible, thereby avoiding the influence on the passband performance or the out-of-band suppression performance of other frequency bands.

[0060] In some embodiments, among the at least three filters, the distance between the adjacent reflective gratings of the adjacent two filters is greater than the distance between the adjacent two reflective gratings of the same filter. Thus, the generation of parasitic capacitance can be reduced, thereby reducing the influence on the passband of the filter, and at the same time, by increasing the distance, the sound waves leaked by one of the reflective gratings can be avoided from being absorbed by the adjacent other reflective grating as much as possible, thereby avoiding the influence on the passband performance or the out-of-band suppression performance of other frequency bands.

[0061] In some embodiments, among the at least three filters, the distance between the adjacent reflective gratings of the adjacent two filters is greater than 8 μm. Thus, the generation of parasitic capacitance can be reduced, thereby reducing the influence on the passband of the filter, and at the same time, by increasing the distance, the sound waves leaked by one of the reflective gratings can be avoided from being absorbed by the adjacent other reflective grating as much as possible, thereby avoiding the influence on the passband performance or the out-of-band suppression performance of other frequency bands. Exemplarily, the distance between the adjacent reflective gratings of the adjacent two filters can be greater than 8 μm, greater than 9 μm, greater than 10 μm, or greater than 11 μm, etc.

[0062] In some embodiments, it can be further defined that among the at least three filters, the distance between the adjacent reflective gratings of the adjacent two filters is greater than 10 μm, so that the generation of parasitic capacitance can be better reduced, thereby reducing the influence on the passband of the filter, and at the same time, by increasing the distance, the sound waves leaked by one of the reflective gratings can be avoided from being absorbed by the adjacent other reflective grating as much as possible, thereby avoiding the influence on the passband performance or the out-of-band suppression performance of other frequency bands.

[0063] In some embodiments, among the at least three filters, a blocking structure is arranged between the adjacent two reflective gratings of the adjacent two resonators, and the blocking structure is used for scattering the leaked sound waves or for absorbing the leaked sound waves. Thus, by the arrangement of the blocking structure, the sound waves leaked by one of the reflective gratings can be avoided from being absorbed by the adjacent other reflective grating as much as possible, thereby avoiding the influence on the passband performance or the out-of-band suppression performance of other frequency bands.

[0064] Exemplarily, the blocking structure can be a scattering structure for scattering the leaked acoustic wave to the chip 10, for example, an arrow structure or other scattering structure made of metal. Exemplarily, the blocking structure can also be a structure such as a slot on the piezoelectric substrate for scattering the leaked acoustic wave to the substrate or for absorbing the leaked acoustic wave, which can avoid affecting other resonators.

[0065] In some embodiments, the bandwidth of the first filter 20 is greater than the bandwidth of any other filter. That is, among all the filters, the bandwidth of the first filter 20 is the largest. In this way, the first filter 20 is allowed to pass a wider range of frequencies, which is suitable for scenarios that require processing of a wide spectrum signal.

[0066] In some embodiments, the first longitudinally-coupled acoustic wave resonator 21 includes at least two dual-mode acoustic surface wave resonators in parallel. In this way, by using two longitudinally-coupled acoustic wave resonators in parallel, the resistance of the first longitudinally-coupled acoustic wave resonator 21 can be reduced, and the passband insertion loss can be reduced.

[0067] In some embodiments, the at least two dual-mode acoustic surface wave resonators in parallel share a reflector between two adjacent dual-mode acoustic surface wave resonators. In this way, while achieving the reduction of the resistance of the first longitudinally-coupled acoustic wave resonator 21 and the reduction of the passband insertion loss, the sharing of the reflector reduces the area of the independent reflector required for each longitudinally-coupled acoustic wave resonator, thereby making the physical layout more compact and helping to reduce the size of the entire device.

[0068] Please refer to Figs. 1-2 In some embodiments, each of the at least three filters includes an input terminal, an output terminal, a ground terminal, and at least one resonant group 60 connected between the input terminal and the output terminal, each resonant group 60 including at least one resonator including two bus bars and a plurality of electrode fingers provided between the two bus bars. Among them, the center distance between two adjacent electrode fingers of the first filter 20 is smaller than the center distance between two adjacent electrode fingers of any other filter. That is, among all the filters, the center distance (usually referred to as pitch) between two adjacent electrode fingers of the first filter 20 is the smallest, so that the center frequency of the first filter 20 is higher, and to some extent, a wider stopband and stronger out-of-band rejection capability can be achieved.

[0069] In some embodiments, each filter includes two ground terminals. In this way, the out-of-band rejection effect of each filter can be guaranteed to enhance the performance of each filter.

[0070] In some embodiments, each of the at least three filters includes an input terminal, an output terminal and a ground terminal, and at least one pair of adjacent filters share a ground terminal. That is, one pair of adjacent filters can share a ground terminal, or two, three or more pairs of adjacent filters can share a ground terminal, so as to reduce the occupied area and facilitate the miniaturization design of the filter device 100.

[0071] Referring to Fig. 2 In some embodiments, the at least three filters include a first filter 20, a second filter 30, a third filter 40 and a fourth filter 50, the first filter 20 is adjacent to the fourth filter 50, the second filter 30 is adjacent to the third filter 40, and the third filter 40 is arranged between the fourth filter 50 and the second filter 30. The first filter 20, the second filter 30, the third filter 40 and the fourth filter 50 are each provided with two ground terminals, one of the ground terminals of the first filter 20 and one of the ground terminals of the fourth filter 50 are the same ground terminal, that is, one of the first ground terminals 24 of the first filter 20 and one of the fourth ground terminals 54 of the fourth filter 50 are the same ground terminal. The other ground terminal of the fourth filter 50 is not shown in the figure. One of the second ground terminals 34 of the second filter 30 and one of the third ground terminals 44 of the third filter 40 are the same ground terminal, and the other second ground terminal 34 of the second filter 30 and the other third ground terminal 44 of the third filter 40 are the same ground terminal, that is, the second filter 30 and the third filter 40 share two ground terminals, so as to reduce the occupied area and facilitate the miniaturization design of the filter device 100. Fig. 2

[0072] In some embodiments, each of the at least three filters includes an input terminal, an output terminal and a ground terminal, and the input terminal and the output terminal of each filter are diagonally arranged. In this way, the coupling between the input terminal and the output terminal can be avoided, so as to avoid affecting the performance of the filter.

[0073] In some embodiments, the at least three filters are all receive filters. The receive filter is used to filter the received signal to extract the signal of the required frequency while suppressing the interference of other frequencies.

[0074] Of course, in other embodiments, the at least three filters integrated on the chip 10 can not all be receive filters, but can also be transmit filters, bandpass filters, bandstop filters, lowpass filters and highpass filters, etc.

[0075] ​In some embodiments, among the at least three filters, a part of the filters is the first group of filters, and another part of the filters is the second group of filters, the frequency band of the first group of filters is higher than that of the second group of filters. Each filter includes a passivation layer, and the film thickness difference of the passivation layer of the first group of filters is smaller than that of the passivation layer of the second group of filters. For example, the first group of filters are high-frequency filters, and the second group of filters are intermediate-frequency filters. In the high-frequency filters, due to the high signal frequency, any slight film thickness change can have a significant impact on the performance of the filter. Therefore, reducing the film thickness difference can ensure that the performance of the filter in the high-frequency band is more stable, thereby making the film thickness difference of the passivation layer of the high-frequency filter relatively small, which helps to improve the frequency stability of the filter.

[0076] It can be understood that the film thickness difference of the passivation layer can be caused by the film thickness difference of the passivation layer of different resonators of the same filter, or by the film thickness difference of the passivation layer of resonators of different filters.

[0077] The embodiments of the present application also provide a radio frequency front-end module, which includes the filter device 100.

[0078] In some embodiments, the radio frequency front-end module can be applied to an electronic device, which can include but is not limited to a tablet computer, a notebook computer, a desktop computer, a navigator, a mobile phone, an electronic watch, and an electronic device or component having a wireless communication function, and the present application does not limit the electronic device.

[0079] In some embodiments, the radio frequency front-end module can further include a low-noise amplifier, a radio frequency switch, and a power amplifier, and the specific connection mode can refer to the prior art, which will not be described here.

[0080] In addition, since the radio frequency front-end module includes the filter device 100, the radio frequency front-end module has all the beneficial effects of the filter device 100, which will not be described here.

[0081] In the case of not contradicting each other, those skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples.

[0082] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed in the present application, and these modifications or replacements should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A filter device, characterized in that, include: chip; At least three filters are integrated on the chip, the at least three filters including a first filter, a second filter and a third filter, the third filter being located between the first filter and the second filter; The first filter includes a first longitudinally coupled acoustic resonator, which includes a plurality of interdigital transducers. The second filter includes a second longitudinally coupled acoustic resonator, which includes a plurality of interdigital transducers; The third filter includes a trapezoidal circuit, which includes at least two series-arm resonators and at least two parallel-arm resonators.

2. The filter device as described in claim 1, characterized in that, Of the at least three filters, the bandwidth of the third filter is less than the bandwidth of any of the other filters.

3. The filter device as described in claim 1, characterized in that, The chip surface has a first region and a second region arranged along a first direction. Of the at least three filters, a portion of the filters are disposed in the first region and another portion of the filters are disposed in the second region. The frequency band of the filter located in the first region is higher than that of the filter located in the second region.

4. The filter device as described in claim 3, characterized in that, In the at least three filters, each filter includes an input terminal, an output terminal, and a ground terminal. In two adjacent filters located in the first region, a first inductor is connected between the input terminal and the ground terminal of one filter, and a second inductor is connected between the input terminal and the ground terminal of the other filter; wherein a grounding structure is provided between the first inductor and the second inductor.

5. The filter device as described in claim 3, characterized in that, The frequency band of the filter located in the first region is greater than 2200MHz and less than or equal to 3000MHz; The frequency range of the filter located in the second region is greater than or equal to 1000MHz and less than or equal to 2200MHz.

6. The filter device as described in claim 3, characterized in that, The first filter is located in the first region, and the first filter and any other filter can perform carrier aggregation.

7. The filter device as claimed in claim 6, characterized in that, The first filter further includes a first input terminal, a first output terminal, a first ground terminal, and a first resonator. One end of the first resonator is connected to the input or output terminal of the first longitudinally coupled acoustic resonator, and the other end of the first resonator is connected to the first ground terminal. An inductor trace is provided between the first longitudinally coupled acoustic resonator and the first resonator, and the width of the inductor trace is 5μm-15μm.

8. The filter device as claimed in claim 1, characterized in that, The chip surface has a first region and a second region arranged along a first direction; The first filter is located on the side of the first region away from the second region, and the second filter is located on the side of the second region away from the first region.

9. The filter device as claimed in claim 8, characterized in that, The first longitudinally coupled acoustic resonator and the second longitudinally coupled acoustic resonator are offset in the first direction, which is perpendicular to the aperture direction of the filter.

10. The filter device as claimed in claim 8, characterized in that, The at least three filters also include a fourth filter, the fourth filter including a third longitudinally coupled acoustic resonator, the third longitudinally coupled acoustic resonator including a plurality of interdigital transducers; The first longitudinally coupled acoustic resonator, the second longitudinally coupled acoustic resonator, and the third longitudinally coupled acoustic resonator are staggered in the first direction, which is perpendicular to the aperture direction of the filter.

11. The filter device as claimed in claim 10, characterized in that, The fourth filter is disposed adjacent to the first filter, and the centerline of the first longitudinally coupled acoustic resonator in the aperture direction is offset from the centerline of the third longitudinally coupled acoustic resonator in the aperture direction.

12. The filter device as claimed in claim 10, characterized in that, The fourth filter is located in the first region, the second filter and the third filter are located in the second region, and the third filter is located between the fourth filter and the second filter.

13. The filter device as claimed in claim 1, characterized in that, In the at least three filters, each filter includes an input terminal, an output terminal, a ground terminal, and at least one resonant group connected between the input terminal and the output terminal, and each resonant group includes at least one resonator; In the at least three filters, the distance between adjacent reflective gratings of two adjacent resonators of the same filter is greater than 3 μm; and / or, In the at least three filters, the distance between adjacent reflector gratings of two adjacent filters is greater than the distance between two adjacent reflector gratings of the same filter; and / or, In the at least three filters, the distance between adjacent reflective gratings of two adjacent filters is greater than 8 μm.

14. The filter device as claimed in claim 13, characterized in that, In the at least three filters, the distance between adjacent reflective gratings of two adjacent resonators of the same filter is greater than 5 μm; and / or, In the at least three filters, the distance between adjacent reflective gratings of two adjacent filters is greater than 10 μm.

15. The filter device as claimed in claim 13, characterized in that, In the at least three filters, a blocking structure is provided between two adjacent reflective grids of two adjacent resonators. The blocking structure is used to scatter or absorb the leaked sound waves.

16. The filter device as claimed in claim 1, characterized in that, The first longitudinally coupled acoustic resonator includes at least two parallel two-mode surface acoustic wave resonators.

17. The filter device as claimed in claim 16, characterized in that, The at least two parallel dual-mode surface acoustic wave resonators share a common reflective grating between adjacent dual-mode surface acoustic wave resonators.

18. The filter device as claimed in claim 1, characterized in that, The bandwidth of the first filter is greater than the bandwidth of any other filter.

19. The filter device as claimed in claim 1, characterized in that, In the at least three filters, each filter includes an input terminal, an output terminal, a ground terminal, and at least one resonant group connected between the input terminal and the output terminal. Each resonant group includes at least one resonator, and the resonator includes two busbars and a plurality of electrode fingers disposed between the two busbars. Wherein, the center distance between two adjacent electrode fingers of the first filter is smaller than the center distance between two adjacent electrode fingers of any other filter.

20. The filter device according to any one of claims 1 to 19, characterized in that, Each of the filters includes two ground terminals; and / or, In the at least three filters, each filter includes an input terminal, an output terminal, and a ground terminal, wherein at least one pair of adjacent filters shares the ground terminal; and / or, In the at least three filters, each filter includes an input terminal, an output terminal, and a ground terminal, and the input terminal and the output terminal of each filter are arranged diagonally.

21. The filter device according to any one of claims 1 to 19, characterized in that, All three filters are receiving filters.

22. The filter device according to any one of claims 1 to 19, characterized in that, Of the at least three filters, a portion of the filters are a first group of filters, and another portion of the filters are a second group of filters, wherein the frequency band of the first group of filters is higher than the frequency band of the second group of filters; Each of the filters includes a passivation layer, and the thickness difference of the passivation layer in the first group of filters is smaller than the thickness difference of the passivation layer in the second group of filters.

23. The filter device according to any one of claims 1 to 19, characterized in that, The first filter further includes a first input terminal, a first output terminal, and a first ground terminal, and the first longitudinally coupled acoustic resonator is connected between the first input terminal and the first output terminal; and / or, The second filter further includes a second input terminal, a second output terminal, and a second ground terminal, with the second longitudinally coupled acoustic resonator connected between the second input terminal and the second output terminal; and / or, The third filter further includes a third input terminal, a third output terminal, and a third ground terminal. The series arm resonator is connected in the series path between the third input terminal and the third output terminal. One end of the parallel arm resonator is connected to the input or output terminal of the series arm resonator, and the other end of the parallel arm resonator is connected to the third ground terminal.

24. A radio frequency front-end module, characterized in that, Includes the filter device as described in any one of claims 1-23.

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