A surface acoustic wave filter

Abstract

The present invention discloses a surface acoustic wave filter, comprising: a supporting substrate, a piezoelectric layer, a resonator component and a heterogeneous mode suppression component; the piezoelectric layer is arranged on the supporting substrate; the resonator component is arranged on the supporting substrate; one end of the heterogeneous mode suppression component is connected to the output end of the resonator component, and the other end of the heterogeneous mode suppression component is grounded; the frequency of the resonance peak of the heterogeneous mode suppression component is consistent with the center frequency of the high-frequency stray mode of the resonator component, and when the lowest frequency excitation mode of the heterogeneous mode suppression component is a zero-order horizontal shear wave mode, the wavelength of the heterogeneous mode suppression component does not exceed a first preset numerical multiple of the resonator component, and when the lowest frequency excitation mode of the heterogeneous mode suppression component is a high-frequency stray mode, the wavelength of the heterogeneous mode suppression component does not exceed a second preset numerical multiple of the wavelength of the resonator component. The present invention can effectively suppress the high-frequency heterogeneous modes generated by the characteristics of the surface acoustic wave resonator material itself, and improve the performance of the surface acoustic wave filter.

Description

Technical Field

[0001] The invention relates to the field of microelectronic technology, in particular to a surface acoustic wave filter. Background Art

[0002] Surface acoustic wave filter is a special filtering device made of piezoelectric materials such as quartz crystal and piezoelectric ceramics, using their piezoelectric effect and the physical characteristics of surface acoustic wave propagation. As a frequency selective device, surface acoustic wave filter is widely used in mobile communication terminals. Surface acoustic wave filter includes resonator, which is a cross-finger electrode structure made on a piezoelectric substrate. The resonator is connected in series or parallel to form a surface acoustic wave filter to complete the filter function.

[0003] Existing resonators are generally ladder-shaped, lattice-shaped or self-cascaded structures. Due to the piezoelectric properties of the material itself, the resonator will produce high-frequency spurious modes at high frequencies. When the prior art uses resonators to form a surface acoustic wave filter, the high-frequency spurious modes will affect the stopband of the surface acoustic wave filter, making it impossible to block the high-frequency signal, resulting in poor performance of the surface acoustic wave filter. Summary of the invention

[0004] The present invention provides a surface acoustic wave filter to solve the technical problem that the high-frequency spurious generated by the existing surface acoustic wave filter affects the stop band, making the high-frequency signal unable to be blocked, resulting in poor performance of the surface acoustic wave filter.

[0005] One embodiment of the present invention provides a surface acoustic wave filter, comprising:

[0006] A support substrate, a piezoelectric layer, a stray mode suppression member, and at least one resonator member;

[0007] The piezoelectric layer is disposed on the supporting substrate;

[0008] At least one of the resonator components is arranged in series on the support substrate;

[0009] One end of the stray mode suppression component is cascade-connected to the supporting substrate, and the other end of the stray mode suppression component is grounded; the frequency of the resonance peak of the stray mode suppression component is consistent with the center frequency of the high-frequency stray mode of the resonator component, and when the lowest frequency excitation mode of the stray mode suppression component is a zero-order horizontal shear wave mode, the wavelength of the stray mode suppression component does not exceed a first preset numerical multiple of the resonator component, and when the lowest frequency excitation mode of the stray mode suppression component is a high-frequency stray mode, the wavelength of the stray mode suppression component does not exceed a second preset numerical multiple of the wavelength of the resonator component.

[0010] Furthermore, the resonator component includes a plurality of resonators, each of which includes a pair of interdigitated electrodes and a reflective grating array arranged on both sides of the pair of interdigitated electrodes; the heterogeneous mode suppression component includes at least one of an interdigitated electrode pair unit and an LC circuit, and the interdigitated electrode pair unit includes a pair of interdigitated electrodes and a reflective grating array arranged on both sides of the pair of interdigitated electrodes.

[0011] Furthermore, when the heterogeneous mode suppression component is an interdigital electrode pair unit, the input end of the interdigital electrode pair is cascade-connected to the supporting substrate, and the output end of the interdigital electrode pair is grounded.

[0012] Furthermore, when the heterogeneous mode suppression component is an LC circuit, an input end of the LC circuit is cascade-connected to the supporting substrate, and an output end of the LC circuit is grounded.

[0013] Further, when the hybrid mode suppression member is a combination of an interdigital electrode pair unit and an LC circuit, one end of the interdigital electrode pair unit is cascade-connected to the support substrate, and the other end of the interdigital electrode pair unit is grounded through the LC circuit; or

[0014] One end of the LC circuit is cascade-connected to the support substrate, and the other end of the LC circuit is grounded through the interdigital electrode pair unit.

[0015] Furthermore, the LC circuit includes an inductor and a capacitor, the inductor includes a circular ring inductor and a square winding inductor, and the capacitor includes a non-excitation mode interdigital electrode array and a parallel plate capacitor.

[0016] Furthermore, the inductance L and the capacitance C in the LC circuit satisfy Wherein, f is a frequency, and the frequency deviation between the frequency and the frequency of the resonator component exciting a high-frequency spurious mode does not exceed a preset threshold range.

[0017] Furthermore, the spacing between adjacent interdigital electrodes in the interdigital electrode pair unit satisfies:

[0018]

[0019] Wherein, p is the spacing between adjacent interdigital electrodes, v is the acoustic velocity of the excitation mode of the interdigital electrode pair unit, corresponding to the acoustic wave propagation velocity of the high-frequency mode of the resonator component, and f ～ The frequency at which high-frequency spurious modes are excited in the resonator member.

[0020] Furthermore, the angle between the sound wave propagation direction of the resonator component and the Y-axis of the material is a preset angle.

[0021] Furthermore, the resonator component includes a plurality of resonators connected in series on the support substrate, and a plurality of resonators connected in cascade on the support substrate.

[0022] The embodiment of the present invention arranges a resonator component on a supporting substrate, and cascade-connects a stray mode suppression component on the supporting substrate, so that the center frequency of the high-frequency stray mode of the resonator component is consistent with the resonance peak of the stray mode suppression component, thereby effectively suppressing the high-frequency stray mode generated by the characteristics of the surface acoustic wave resonator material itself, and further effectively improving the performance of the surface acoustic wave filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of a surface acoustic wave filter provided by an embodiment of the present invention;

[0024] Figure 2 is another structural schematic diagram of a surface acoustic wave filter provided by an embodiment of the present invention;

[0025] Figure 3 is another structural schematic diagram of a surface acoustic wave filter provided by an embodiment of the present invention;

[0026] Figure 4 is another structural schematic diagram of a surface acoustic wave filter provided by an embodiment of the present invention;

[0027] Figure 5 It is a schematic diagram of a connection between a heterogeneous mode suppression component and a supporting substrate provided by an embodiment of the present invention;

[0028] Figure 6 Schematic diagram of two shapes of inductor structures provided by embodiments of the present invention;

[0029] Figure 7 Schematic diagram of capacitor structures of two shapes provided in an embodiment of the present invention;

[0030] Figure 8 is a schematic diagram of frequency response curves of surface acoustic wave filters with different structures provided by an embodiment of the present invention;

[0031] Fig. 9 is a schematic diagram of a frequency response curve of a surface acoustic wave filter provided by an embodiment of the present invention;

[0032] Fig.10 It is a schematic diagram of a 3D periodic unit block cut of a heterogeneous integrated surface acoustic wave resonator provided by an embodiment of the present invention;

[0033] Fig.11 is a top view of a heterogeneous integrated surface acoustic wave resonator provided by an embodiment of the present invention;

[0034] Fig.12It is a side view of a heterogeneous integrated surface acoustic wave resonator provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0037] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] See also Figure 1 One embodiment of the present invention provides a surface acoustic wave filter, comprising:

[0039] A support substrate 10, a piezoelectric layer, a stray mode suppression member 30 and at least one resonator member 20;

[0040] The piezoelectric layer is disposed on the supporting substrate 10;

[0041] At least one of the resonator components 20 is arranged in series on the support substrate 10;

[0042] See also Figure 2In the embodiment of the present invention, the piezoelectric layer can be made of X-cut lithium niobate or YX-cut lithium tantalate. When the piezoelectric layer is made of X-cut lithium niobate, the angle θ between the sound wave propagation angle of the resonator component 20 and the Y axis of the material is 0°-20°, and the lowest frequency excitation mode is the zero-order horizontal shear wave mode (SHO mode) of the sound wave. The angle α between the sound wave propagation angle and the Y axis of the material in the heterogeneous mode suppression component 30 is 42°-58°, and the lowest frequency excitation mode is the S0 mode (high-frequency heterogeneous mode scattering mode) of the sound wave. The resonator component 20 excites two modes: the low-frequency SH0 mode (zero-order horizontal shear wave mode) and the high-frequency S0 mode (high-frequency heterogeneous mode scattering mode).

[0043] See also Figure 3 When the piezoelectric layer uses YX-cut lithium tantalate, the angle θ between the sound wave propagation angle of the resonator component 20 and the material Y axis is -5°-5°, preferably 0°, and the lowest frequency excitation mode is the zero-order horizontal shear wave mode of the sound wave. The angle α between the sound wave propagation angle and the material Y axis in the heterogeneous mode suppression component 30 is 42°-46°, preferably 44°, and the lowest frequency excitation mode is the S0 mode of the sound wave (high-frequency heterogeneous mode scattering mode). The resonator component 20 excites two modes: the low-frequency SH0 mode (zero-order horizontal shear wave mode) and the high-frequency S0 mode (high-frequency heterogeneous mode scattering mode).

[0044] Optionally, the resonator member 20 includes a plurality of resonators 201 , several resonators 201 are connected in series on the support substrate 10 , and several resonators 201 are connected in cascade on the support substrate 10 .

[0045] The piezoelectric layer includes piezoelectric materials such as lithium niobate / lithium tantalate; the support substrate 10 includes at least one of α-aluminum oxide, silicon carbide and silicon oxide. The piezoelectric layer is arranged on the support substrate 10, and an electrode is also arranged on the piezoelectric layer, and the material of the electrode is at least one of aluminum, copper, gold, platinum, silver, etc. The resonator component 20 and the heterogeneous mode suppression component also include a dielectric layer, which is located between the support substrate 10 and the piezoelectric layer and can be a silicon dioxide dielectric layer.

[0046] One end of the stray mode suppression component 30 is cascade-connected to the supporting substrate 10, and the other end of the stray mode suppression component 30 is grounded; the frequency of the resonance peak of the stray mode suppression component 30 is consistent with the center frequency of the high-frequency stray mode of the resonator component 20, and when the lowest frequency excitation mode of the stray mode suppression component 30 is a zero-order horizontal shear wave mode, the wavelength of the stray mode suppression component 30 does not exceed a first preset numerical multiple of the resonator component 30, and when the lowest frequency excitation mode of the stray mode suppression component 30 is a high-frequency stray mode, the wavelength of the stray mode suppression component 30 does not exceed a second preset numerical multiple of the wavelength of the resonator component 20.

[0047] In an embodiment of the present invention, the first preset value is the ratio of the center frequency of the high-frequency spurious mode of the resonator component to the passband center frequency of the resonator component. In a preferred embodiment, the first preset value is 0.5. The second preset value is the sound velocity ratio of the center frequency of the high-frequency spurious mode of the resonator component to the passband center frequency of the resonator component. In a preferred embodiment, the second preset value is 1.3. When the admittance of the spurious mode suppression component within the preset frequency range is greater than -25dB, and the difference between the frequency at which the resonance peak of the spurious mode suppression component 30 is located within the preset range of frequencies and the center frequency of the high-frequency spurious mode of the resonator component 20 is within the preset threshold range, it is judged that the frequency at which the resonance peak of the spurious mode suppression component 30 is located is consistent with the passband center frequency of the resonator component 20. Optionally, the frequency range of ±5Hz of the frequency at which the resonance peak of the spurious mode suppression component 30 is located can be used as the preset frequency range, and the preset frequency range can also be adjusted according to actual needs. In the embodiment of the present invention, a resonator component 20 is arranged on a supporting substrate 10, and a stray mode suppression component 30 is cascade-connected on the supporting substrate 10, so that the center frequency of the high-frequency stray mode of the resonator component 20 is consistent with the resonance peak of the stray mode suppression component 30, thereby effectively suppressing the high-frequency stray mode generated by the material characteristics of the surface acoustic wave resonator 201 itself, and further effectively improving the performance of the surface acoustic wave filter.

[0048] Optionally, the cascade connection between the heterogeneous mode suppression member 30 and the supporting substrate 10 may include three connection situations:

[0049] Since at least one resonator component 20 is connected in series and arranged on the supporting substrate, at least one resonator component 20 can be regarded as an integral resonator component, and the integral resonator component includes an input end and an output end, (1) the stray mode suppression component 30 can be cascade-connected to the supporting substrate 10 at the input end of the integral resonator component; (2) the stray mode suppression component 30 can also be cascade-connected to the supporting substrate 10 at the output end of the integral resonator component; (3) one end of the stray mode suppression component 30 can be cascade-connected to the supporting substrate 10 between two resonator components 20. Please refer to 5, which is a schematic diagram of the cascade connection of one end of the stray mode suppression component 30 and the supporting substrate between two resonator components 20 provided in an embodiment of the present invention.

[0050] Optionally, the cascade connection in the embodiment of the present invention includes a parallel connection and a series connection.

[0051] In one embodiment, the resonator component 20 includes a plurality of resonators, each of which includes an interdigitated electrode pair and a reflective grating array disposed on both sides of the interdigitated electrode pair; the heterogeneous mode suppression component 30 includes at least one of an interdigitated electrode pair unit and an LC circuit, each of which includes an interdigitated electrode pair and a reflective grating array disposed on both sides of the interdigitated electrode pair.

[0052] In one embodiment, when the heterogeneous mode suppression member 30 is an interdigital electrode pair unit, the input end of the interdigital electrode pair is cascade-connected to the support substrate 10 , and the output end of the interdigital electrode pair is grounded.

[0053] In the embodiment of the present invention, the interdigital electrode pairs and the reflective grating arrays arranged on both sides of the interdigital electrode pairs constitute an interdigital electrode pair unit, namely, a stray mode suppression resonator 201. The number of interdigital pairs, the number of reflective gratings and the aperture length of the stray mode suppression resonator 201 are all smaller than the resonator 201 in the resonator component 20, and the frequency corresponding to the maximum value of the admittance curve of the stray mode suppression resonator 201 is less than 0.5 GHz from the frequency offset of the high-frequency spurious mode excited by the resonator component 20.

[0054] Please continue reading Figure 2 In a specific embodiment, the support substrate 10 has a thickness of 300 nanometers and is a composite substrate of lithium tantalate-silicon dioxide-sapphire with a YX42 cut shape. The electrodes arranged on the support substrate 10 are made of metal aluminum. Four series resonators 201 and three cascade resonators 201 are manufactured on the support substrate 10 to form a resonator component 20, with a center frequency of 2.1 GHz and a passband frequency of 1.5-2.7 GHz. The working mode of the resonator 201 at the passband is the SH0 mode. The resonator component 20 has a high-frequency spurious mode at frequencies of 4.1 GHz and 4.3 GHz. Correspondingly, the filter of the embodiment of the present invention has a high-frequency passband at about 4.2 GHz, a passband frequency range of 4.1 GHz to 4.3 GHz, a passband center frequency of 4.2 GHz, and a working mode of a high-frequency spurious mode. After the stray mode suppression resonator 201 is set in the embodiment of the present invention, the lowest working mode of the stray mode suppression resonator 201 is a high-frequency stray mode, the frequency of the resonance peak is 4.2GHz, the frequency of the anti-resonance peak is 4.8GHz, and the admittance value of the highest point of the resonance peak is -6dB. After adding the stray mode suppression resonator 201, the passband performance of the surface acoustic wave filter does not deteriorate significantly, and the stopband parameter decreases from -15dB to about -30dB, thereby effectively improving the stopband suppression performance.

[0055] In one embodiment, when the stray mode suppression member 30 is an LC circuit, an input end of the LC circuit is cascade-connected to the support substrate 10 , and an output end of the LC circuit is grounded.

[0056] In the embodiment of the present invention, the LC circuit includes an inductor and a capacitor, one end of the inductor is connected to the output end of the resonator component 20, and the other end of the inductor is grounded through the capacitor.

[0057] In one embodiment, when the hybrid mode suppression member 30 is a combination of an interdigital electrode pair unit and an LC circuit, one end of the interdigital electrode pair unit is cascade-connected to the support substrate 10, and the other end of the interdigital electrode pair unit is grounded through the LC circuit; or

[0058] One end of the LC circuit is cascade-connected to the support substrate 10 , and the other end of the LC circuit is grounded through the interdigital electrode pair unit.

[0059] See also Figure 6-7 The LC circuit includes an inductor and a capacitor, wherein the inductor includes a circular ring inductor and a square winding inductor, and the capacitor includes a non-excitation mode interdigital electrode array and a parallel plate capacitor.

[0060] Please continue reading Figure 4 In a specific embodiment, the support substrate 10 is a composite substrate of lithium tantalate-silicon dioxide-sapphire with a thickness of 300 nanometers and a YX42 cut shape, and the electrode disposed on the support substrate 10 is a metal aluminum electrode. Four series resonators 201 and three cascade resonators 201 are manufactured on the support substrate 10 to form a resonator component 20, with a center frequency of 2.1 GHz, a passband frequency of 1.5-2.7 GHz, and an operating mode of the resonator 201 at the passband being an SH0 mode. The resonator component 20 has a high-frequency spurious mode at 4.1 GHz and 4.3 GHz, and the corresponding surface acoustic wave filter has a high-frequency passband at about 4.2 GHz, a passband frequency range of 4.1 GHz to 4.3 GHz, a passband center frequency of 4.2 GHz, and an operating mode of a high-frequency spurious mode. After adding the series LC circuit, where the inductance is L=1.2nH and the capacitance is C=1.2pF, where both the inductance and the capacitance are manufactured by the ipd process, the resonance peak frequency is 4.2GHz, and the admittance value of the highest point of the resonance peak is -6dB. In the embodiment of the present invention, the LC circuit is used as the heterogeneous mode suppression component 30. After adding the series capacitor and inductance, the passband performance of the surface acoustic wave filter does not deteriorate significantly, and the stopband parameter drops from -15dB to about -33dB, thereby effectively improving the stopband suppression performance.

[0061] In one embodiment, the inductance L and the capacitance C in the LC circuit satisfy Wherein, f is a frequency, and the frequency deviation from the frequency of the resonator component 20 exciting a high-frequency spurious mode does not exceed a preset threshold range.

[0062] In one embodiment, the spacing between adjacent interdigital electrodes in the interdigital electrode pair unit satisfies:

[0063]

[0064] Wherein, p is the spacing between adjacent interdigital electrodes, v is the acoustic velocity of the excitation mode of the interdigital electrode pair unit, corresponding to the acoustic wave propagation velocity of the high-frequency mode of the resonator component, and f ～ The frequency at which high-frequency spurious modes are excited in the resonator member.

[0065] In one embodiment, the angle between the sound wave propagation direction of the resonator component 20 and the Y-axis of the material is a preset angle.

[0066] In one embodiment, the preset angle is θ=12°.

[0067] In one embodiment, the resonator member 20 includes a plurality of resonators 201 connected in series on the support substrate 10 , and a plurality of resonators 201 connected in cascade on the support substrate 10 .

[0068] In the embodiment of the present invention, four resonators 201 are connected in series on the support substrate 10, and three resonators 201 are connected in cascade on the support substrate 10. The number of series resonators 201 and the number of cascade resonators 201 can also be set according to actual needs.

[0069] See also Figure 8 , which is a schematic diagram of frequency response curves of surface acoustic wave filters of different structures provided in an embodiment of the present invention; please refer to Fig. 9 , which is a schematic diagram of a frequency response curve of a surface acoustic wave filter provided in an embodiment of the present invention.

[0070] Optionally, the method for preparing the surface acoustic wave filter according to the embodiment of the present invention includes:

[0071] A heterogeneous integrated support substrate is prepared using ion beam stripping and bonding technology, including: ion implantation, bonding, stripping, polishing and other processes; a lift-off process is used to make a pair of interdigitated electrodes on the support substrate, including: spinning, photolithography, deposition and stripping processes, wherein the metal structure of the resonator component (including the interdigitated electrode pair and the reflective grid) is formed in the photolithography step; the interdigitated electrode pair and the reflective grid of the heterogeneous mode suppression component are formed; the inductance of the heterogeneous mode suppression component is formed, and the capacitance of the heterogeneous mode suppression component is formed by an etching method.

[0072] See also Figure 10-12 The resonator component of the embodiment of the present invention can also be a heterogeneous integrated surface acoustic wave resonator. The heterogeneous integrated surface acoustic wave resonator component and the heterogeneous mode suppression component are both manufactured on a heterogeneous integrated substrate. The heterogeneous integrated substrate includes a support substrate and a piezoelectric layer. The support substrate may include a variety of composite materials, such as at least one of silicon carbide, silicon dioxide, sapphire, silicon and quartz. The piezoelectric layer may include lithium niobate and lithium tantalate of different cut types. Optionally, the thickness of the piezoelectric layer is 300-600 nanometers.

[0073] The implementation of the embodiments of the present invention has the following beneficial effects:

[0074] In the embodiment of the present invention, a resonator component 20 is arranged on a supporting substrate 10, and a stray mode suppression component 30 is cascade-connected on the supporting substrate 10, so that the center frequency of the high-frequency stray mode of the resonator component 20 is consistent with the resonance peak of the stray mode suppression component 30, thereby effectively suppressing the high-frequency stray mode generated by the material characteristics of the surface acoustic wave resonator 201 itself, and further effectively improving the performance of the surface acoustic wave filter.

[0075] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A surface acoustic wave filter, It is characterized in that include: A support substrate, a piezoelectric layer, a stray mode suppression member, and at least one resonator member; The piezoelectric layer is disposed on the supporting substrate; At least one of the resonator components is arranged in series on the support substrate; One end of the heterogeneous mode suppression component is cascade-connected to the supporting substrate, and the other end of the heterogeneous mode suppression component is grounded; the frequency of the resonance peak of the heterogeneous mode suppression component is consistent with the center frequency of the high-frequency spurious mode of the resonator component, and when the lowest frequency excitation mode of the heterogeneous mode suppression component is a zero-order horizontal shear wave mode, the wavelength of the heterogeneous mode suppression component does not exceed a first preset numerical multiple of the resonator component, and when the lowest frequency excitation mode of the heterogeneous mode suppression component is a high-frequency spurious mode, the wavelength of the heterogeneous mode suppression component does not exceed a second preset numerical multiple of the wavelength of the resonator component, wherein the first preset numerical value is the ratio of the center frequency of the high-frequency heterogeneous mode of the resonator component to the passband center frequency of the resonator component, and the second preset numerical value is the sound velocity ratio of the high-frequency heterogeneous mode center frequency of the resonator component to the passband center frequency of the resonator component.

2. The surface acoustic wave filter according to claim 1, It is characterized in that The resonator component includes a plurality of resonators, each of which includes an interdigitated electrode pair and a reflective grating array arranged on both sides of the interdigitated electrode pair; the heterogeneous mode suppression component includes at least one of an interdigitated electrode pair unit and an LC circuit, each of which includes an interdigitated electrode pair and a reflective grating array arranged on both sides of the interdigitated electrode pair.

3. The surface acoustic wave filter according to claim 2, It is characterized in that When the heterogeneous mode suppression member is an interdigital electrode pair unit, the input end of the interdigital electrode pair is cascade-connected to the support substrate, and the output end of the interdigital electrode pair is grounded.

4. The surface acoustic wave filter according to claim 2, It is characterized in that When the stray mode suppression component is an LC circuit, an input end of the LC circuit is cascade-connected to the support substrate, and an output end of the LC circuit is grounded.

5. The surface acoustic wave filter according to claim 2, It is characterized in that When the hybrid mode suppression member is a combination of an interdigital electrode pair unit and an LC circuit, one end of the interdigital electrode pair unit is cascade-connected to the support substrate, and the other end of the interdigital electrode pair unit is grounded through the LC circuit; or One end of the LC circuit is cascade-connected to the support substrate, and the other end of the LC circuit is grounded through the interdigital electrode pair unit.

6. The surface acoustic wave filter according to claim 2, It is characterized in that The LC circuit includes an inductor and a capacitor, wherein the inductor includes a circular ring inductor and a square winding inductor, and the capacitor includes a non-excitation mode interdigital electrode array and a parallel plate capacitor.

7. The surface acoustic wave filter according to claim 2, It is characterized in that The inductance L and capacitance C in the LC circuit satisfy Wherein, f is a frequency, and the frequency deviation between the frequency and the frequency of the resonator component exciting a high-frequency spurious mode does not exceed a preset threshold range.

8. The surface acoustic wave filter according to claim 2, It is characterized in that The spacing between adjacent interdigital electrodes in the interdigital electrode pair unit satisfies: Wherein, p is the spacing between adjacent interdigital electrodes, v is the acoustic velocity of the excitation mode of the interdigital electrode pair unit, corresponding to the acoustic wave propagation velocity of the high-frequency mode of the resonator component, and f ～ The frequency at which high-frequency spurious modes are excited in the resonator member.

9. The surface acoustic wave filter according to claim 1, It is characterized in that The angle between the sound wave propagation direction of the resonator component and the Y-axis of the material is a preset angle.

10. The surface acoustic wave filter according to claim 1, It is characterized in that The resonator member includes a plurality of resonators connected in series on the support substrate, and a plurality of resonators connected in cascade on the support substrate.

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