Resonator, filter and electronic device

Abstract

The application relates to a resonator, a filter and an electronic device, the resonator comprising a piezoelectric substrate and an interdigital transducer arranged on the piezoelectric substrate; the interdigital transducer comprises oppositely arranged first bus bars and second bus bars, first interdigital electrodes and first ground dummy fingers connected with the first bus bars are arranged between the first bus bars and the second bus bars, second interdigital electrodes and second ground dummy fingers connected with the second bus bars are arranged between the first bus bars and the second bus bars, and the first interdigital electrodes are oppositely arranged with the second ground dummy fingers; the interdigital transducer further comprises first suspended dummy fingers and second suspended dummy fingers, the first suspended dummy fingers are arranged between the first interdigital electrodes and the second ground dummy fingers and are spaced apart from the first interdigital electrodes and the second ground dummy fingers, and the second suspended dummy fingers are arranged between the second interdigital electrodes and the first ground dummy fingers and are spaced apart from the second interdigital electrodes and the first ground dummy fingers. The resonator provided by the application has a high quality factor.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to resonators, filters and electronic devices. Background Technology

[0002] Surface acoustic wave (SAW) resonators, as core passive devices in radio frequency (RF) front-ends, are widely used in mobile communications, radar, and sensing. The core structure of a SAW resonator typically consists of a piezoelectric substrate and interdigital transducers mounted on the piezoelectric substrate.

[0003] In related technologies, the acoustic field distribution of SAW resonators is optimized by introducing a pseudo-finger structure into the interdigital transducer. However, the design of the pseudo-finger structure in these technologies reduces the quality factor (Q value) of the resonator. Summary of the Invention

[0004] Therefore, it is necessary to provide a resonator, filter, and electronic device to address the problem that the design of pseudo-finger structures in related technologies reduces the quality factor of the resonator.

[0005] In a first aspect, one embodiment of this application provides a resonator, which includes: a piezoelectric substrate and an interdigital transducer disposed on the piezoelectric substrate;

[0006] The interdigital transducer includes a first busbar and a second busbar arranged opposite to each other. A first interdigital electrode and a first grounding dummy finger are disposed between the first busbar and the second busbar, and a second interdigital electrode and a second grounding dummy finger are disposed between the first busbar and the second busbar. The first interdigital electrode and the first grounding dummy finger are arranged alternately at intervals along the extension direction of the first busbar, and the second interdigital electrode and the second grounding dummy finger are arranged alternately at intervals along the extension direction of the second busbar. The first interdigital electrode and the second grounding dummy finger are arranged opposite to each other, and the second interdigital electrode and the first grounding dummy finger are arranged opposite to each other.

[0007] The interdigital transducer also includes a first floating pseudo-finger and a second floating pseudo-finger. The first floating pseudo-finger is disposed between the first interdigital electrode and the second grounding pseudo-finger, and is spaced apart from the first interdigital electrode and the second grounding pseudo-finger. The second floating pseudo-finger is disposed between the second interdigital electrode and the first grounding pseudo-finger, and is spaced apart from the second interdigital electrode and the first grounding pseudo-finger.

[0008] In one embodiment, a first gap is included between the first levitating spur and the first interdigital electrode, and a second gap is included between the first levitating spur and the second grounded spur; the size of the first gap and the size of the second gap are the same along the extending direction of the first interdigital electrode.

[0009] A third gap is included between the second floating spur and the second interdigital electrode, and a fourth gap is included between the second floating spur and the first grounding spur; the dimensions of the third gap and the fourth gap are the same along the extension direction of the second interdigital electrode.

[0010] In one embodiment, the dimension of the first gap is greater than or equal to 0.1 along the extending direction of the first interdigital electrode. And less than or equal to 0.4 ;

[0011] Along the extending direction of the second interdigital electrode, the dimension of the third gap is greater than or equal to 0.1. And less than or equal to 0.4 , The arrangement period of the interdigital transducers.

[0012] In one embodiment, the first levitating pseudofinger includes at least two first sub-levitating pseudofingers, with adjacent first sub-levitating pseudofingers spaced apart.

[0013] The second floating pseudofinger includes at least two second sub-floating pseudofingers, with an interval between adjacent second sub-floating pseudofingers.

[0014] In one embodiment, a fifth gap is included between two adjacent first sub-suspended prosthetic fingers along the extension direction of the first interdigital electrode, and the size of the fifth gap is the same as the size of the first gap.

[0015] A sixth gap is included between two adjacent second sub-suspended prosthetic fingers, along the extension direction of the second interdigital electrode, and the size of the sixth gap is the same as that of the third gap.

[0016] In one embodiment, the size of the first grounding dummy finger is greater than or equal to 0.5 along the extending direction of the first grounding dummy finger. And less than or equal to 1.0 ;

[0017] Along the extension direction of the second grounding dummy finger, the size of the second grounding dummy finger is greater than or equal to 0.5. And less than or equal to 1.0 .

[0018] In one embodiment, the piezoelectric substrate includes a substrate and a piezoelectric layer disposed on the substrate.

[0019] In one embodiment, the resonator further includes a reflector disposed on a piezoelectric substrate;

[0020] Along the extension direction of the first busbar in the interdigital transducer, reflectors are disposed on opposite sides of the interdigital transducer.

[0021] Secondly, one embodiment of this application provides a filter including the resonator as described in the first aspect above.

[0022] Thirdly, one embodiment of this application provides an electronic device including the filter provided in the second aspect above.

[0023] The aforementioned resonator, filter, and electronic device include a resonator comprising a piezoelectric substrate and an interdigital transducer disposed on the piezoelectric substrate; the interdigital transducer includes a first busbar and a second busbar disposed opposite to each other, a first interdigital electrode and a first grounding dummy finger disposed between the first busbar and the second busbar, and a second interdigital electrode and a second grounding dummy finger disposed between the first busbar and the second busbar, the first interdigital electrode and the first grounding dummy finger being alternately spaced along the extension direction of the first busbar, and the second interdigital electrode and the second grounding dummy finger being alternately spaced along the extension direction of the second busbar; the first interdigital electrode and the second grounding dummy finger are disposed opposite to each other; the interdigital transducer further includes a first floating dummy finger and a second floating dummy finger, the first floating dummy finger being disposed between the first interdigital electrode and the second grounding dummy finger and spaced apart from the first interdigital electrode and the second grounding dummy finger, and the second floating dummy finger being disposed between the second interdigital electrode and the first grounding dummy finger and spaced apart from the second interdigital electrode and the first grounding dummy finger. In this embodiment, the first and second suspended pseudo-fingers are electrically suspended. When the interdigital transducer is working, the first and second suspended pseudo-fingers can generate induced charges through electromechanical coupling, thereby forming a dynamically floating induced potential. This induced potential can automatically correct the non-uniform electric field caused by geometric abrupt changes at the ends of the first and second interdigital electrodes, achieving "smoothing" of the electric field intensity. This eliminates strong electric field gradients and suppresses high-order transverse parasitic modes excited by the first and second grounded pseudo-fingers due to electric field distortion at the source. Furthermore, the arrangement of the first and second suspended pseudo-fingers can create a reflective interface at the edge of the acoustic aperture. This reflective interface acts as an acoustic barrier, effectively confining the primary mode acoustic energy in the resonator within the effective acoustic aperture region, significantly reducing energy scattering and diffraction losses towards the first and second busbars, thereby improving the quality factor of the resonator. Attached Figure Description

[0024] Figure 1 A schematic diagram of the resonator provided for one embodiment.

[0025] Figure 2 This is a schematic diagram of an interdigital transducer provided in one embodiment.

[0026] Figure 3 A schematic diagram of the structure of an interdigital transducer provided for another embodiment.

[0027] Figure 4Simulation comparison curves of admittance and conductance as a function of frequency for different structures of an interdigital transducer provided for one embodiment.

[0028] Figure 5 Simulation comparison curves showing the quality factor versus frequency for different structures of an interdigital transducer provided in one embodiment.

[0029] Figure 6 The figure shows a simulation comparison of admittance and conductance versus frequency under equal and non-equal spacing conditions for an interdigital transducer with a double-density suspended pseudofinger structure provided in one embodiment.

[0030] Figure 7 A schematic diagram of the resonator provided for another embodiment.

[0031] Explanation of reference numerals in the attached figures:

[0032] 100. Piezoelectric substrate; 200. Interdigital transducer; 210. First busbar; 220. Second busbar; 230. First interdigital electrode; 240. First ground dummy finger; 250. Second interdigital electrode; 260. Second ground dummy finger; 270. First floating dummy finger; 271. First sub-floating dummy finger; 280. Second floating dummy finger; 281. Second sub-floating dummy finger; 300. Reflector. Detailed Implementation

[0033] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0034] In the description of this application, it should be understood that if terms such as "length", "width", "thickness", "upper", "lower", "vertical", "horizontal", etc. appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0035] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "at least two" appears, it means two, three, etc., unless otherwise explicitly specified.

[0036] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0037] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0038] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0039] First, before introducing the technical solutions of the embodiments disclosed in this application, the background technology or technological evolution on which the embodiments of this application are based will be introduced. In the field of communication technology, surface acoustic wave (SAW) resonators, as core passive devices of radio frequency front-ends, are widely used in mobile communication, radar, and sensing fields. The core structure of a SAW resonator typically consists of a piezoelectric substrate and an interdigital transducer (IDT) disposed on the piezoelectric substrate. The IDT electrode strips utilize the electromechanical coupling effect of piezoelectric materials to achieve precise conversion of electro-acoustic signals, and their structural parameters directly determine the quality factor (Q value) and electromechanical coupling coefficient (K value) of the resonator. 2 Key performance indicators such as frequency stability.

[0040] As 5G / 6G communication systems evolve towards millimeter-wave high-frequency bands, more stringent requirements are placed on the performance of resonators. In high-frequency scenarios above 6 GHz, SAW resonators in related technologies face severe performance bottlenecks. First, the edge effects and acoustic wave diffraction phenomena of the electrode fingers become increasingly significant, easily leading to scattering of sound waves at the electrode edges, causing significant energy loss, and consequently resulting in a substantial decrease in Q value and an increase in insertion loss. Second, non-uniform electric fields at high frequencies easily excite parasitic modes and higher-order spurious resonances, destroying stopband suppression characteristics and severely affecting the spectral purity of the filter. To optimize the acoustic field distribution, related technologies often introduce "dummy" structures at the ends of the IDT (Integrated Device Transformer) fingers. However, the dummy structures in related technologies typically employ a grounded design, which not only introduces additional parasitic capacitance, limiting the flexibility of structural parameter adjustment, but also has limited suppression capability for higher-order spurious signals at high frequencies. Ordinary dummy structures still exhibit significant spurious peaks at certain high-frequency bands, and have low Bode-Q values, making it difficult to meet the requirements of next-generation high-speed communication for ultra-low loss and high suppression performance. In response, this application provides a resonator with a higher quality factor, i.e., with superior performance.

[0041] The technical solution of this application and how the technical solution of this application solves the technical problem are described in detail below with specific embodiments.

[0042] In one embodiment, such as Figure 1 As shown, a resonator is provided, including a piezoelectric substrate 100 and an interdigital transducer 200 disposed on the piezoelectric substrate 100.

[0043] The piezoelectric substrate 100 and the interdigital transducer 200 are stacked in a direction perpendicular to the ground.

[0044] The interdigital transducer 200 includes a first busbar 210 and a second busbar 220 disposed opposite to each other. A first interdigital electrode 230 and a first grounding dummy finger 240 connected to the first busbar 210 are disposed between the first busbar 210 and the second busbar 220, and a second interdigital electrode 250 and a second grounding dummy finger 260 are connected to the second busbar 220. The first interdigital electrode 230 and the first grounding dummy finger 240 are arranged alternately at intervals along the extension direction of the first busbar 210, and the second interdigital electrode 250 and the second grounding dummy finger 260 are arranged alternately at intervals along the extension direction of the second busbar 220. The first interdigital electrode 230 and the second grounding dummy finger 260 are disposed opposite to each other, and the second interdigital electrode 250 and the first grounding dummy finger 240 are disposed opposite to each other.

[0045] It is understood that the first busbar 210 and the second busbar 220 extend along a first direction (X direction, i.e., the wave propagation direction) and are positioned opposite each other in a second direction (Y direction). The first and second directions intersect. The first busbar 210 and the second busbar 220 can be arranged parallel to each other (e.g., ...). Figure 1 As shown), there may also be a certain angle between the first busbar 210 and the second busbar 220. Along the second direction (Y direction) perpendicular to the first direction, a first interdigital electrode 230, a second interdigital electrode 250, a first grounding dummy finger 240 and a second grounding dummy finger 260 are provided between the first busbar 210 and the second busbar 220.

[0046] Both the first interdigital electrode 230 and the first grounding dummy finger 240 are electrically connected to the first busbar 210, and are spaced apart. The first interdigital electrode 230 and the first grounding dummy finger 240 can be arranged parallel to each other. Along the Y direction, the length of the first interdigital electrode 230 is greater than the length of the first grounding dummy finger 240. Along the X direction, the first interdigital electrode 230 and the first grounding dummy finger 240 are arranged alternately at intervals.

[0047] The second interdigital electrode 250 and the second grounding dummy finger 260 are both electrically connected to the second busbar 220, and are spaced apart. The second interdigital electrode 250 and the second grounding dummy finger 260 can be arranged parallel to each other. Along the Y-direction, the length of the second interdigital electrode 250 is greater than the length of the second grounding dummy finger 260. Along the Y-direction, the second interdigital electrode 250 and the second grounding dummy finger 260 are arranged alternately. The second interdigital electrode 250 is opposite to and spaced apart from the first grounding dummy finger 240, and the second grounding dummy finger 260 is opposite to and spaced apart from the first interdigital electrode 230.

[0048] Along the X direction, the interval region between the first interdigital electrode 230 and the second interdigital electrode 250 (i.e. Figure 1The area enclosed by the dashed line and the first interdigital electrode 230 and the second interdigital electrode 250 is the acoustic aperture H of the resonator. Along the X direction, starting from the left side of the first interdigital electrode 230 and ending at the left side of the second interdigital electrode 230, the arrangement period of the interdigital transducers 200 is formed. Specifically, the interdigital transducer 200 may include 70 to 100 arrangement cycles. The specific arrangement period of the interdigital transducers in the 200 The quantity can be 70, 80, 90 or 100.

[0049] In an optional embodiment, such as Figure 1 As shown, along the X direction, the width of the end of the first interdigital electrode 230 and the position of the first interdigital electrode 230 corresponding to the end of the second interdigital electrode 250 is greater than the width of other positions of the first interdigital electrode 230; the width of the end of the second interdigital electrode 250 and the position of the second interdigital electrode 250 corresponding to the end of the first interdigital electrode 230 is greater than the width of other positions of the second interdigital electrode 250.

[0050] The interdigital transducer 200 also includes a first floating pseudo-finger 270 and a second floating pseudo-finger 280. The first floating pseudo-finger 270 is disposed between the first interdigital electrode 230 and the second grounding pseudo-finger 260, and is spaced apart from the first interdigital electrode 230 and the second grounding pseudo-finger 260. The second floating pseudo-finger 280 is disposed between the second interdigital electrode 250 and the first grounding pseudo-finger 240, and is spaced apart from the second interdigital electrode 250 and the first grounding pseudo-finger 240.

[0051] Understandably, along the Y-direction, there is a gap between the first interdigital electrode 230 and the second grounded dummy finger 260. The first levitating dummy finger 270 is disposed within this gap and is not connected to either the first interdigital electrode 230 or the second grounded dummy finger 260. Similarly, there is a gap between the second interdigital electrode 250 and the first grounded dummy finger 240. The second levitating dummy finger 280 is disposed within this gap and is not connected to either the second interdigital electrode 250 or the first grounded dummy finger 240. The first levitating dummy finger 270 and the second levitating dummy finger 280 are disposed on the piezoelectric substrate 100 without etching the piezoelectric substrate 100. In other words, the first levitating dummy finger 270 and the second levitating dummy finger 280 are independent metal blocks located on the surface of the piezoelectric substrate 100 without etching the piezoelectric substrate 100, and are electrically in a completely ungrounded levitated state. It should be noted that the levitation state of the first levitation finger 270 and the second levitation finger 280 means that the first levitation finger 270 and the second levitation finger 280 are not connected to the first interdigital electrode 230, the first grounding finger 240, the second interdigital electrode 250, the second grounding finger 260, the first bus bar 210 and the second bus bar 220. A dielectric layer may be provided between the first levitation finger 270 and the second levitation finger 280 and the piezoelectric substrate 100. The first levitation finger 270, the second levitation finger 280, the first interdigital electrode 230, the first grounding finger 240, the second interdigital electrode 250, the second grounding finger 260, the first bus bar 210 and the second bus bar 220 may all be formed on the surface of the piezoelectric substrate 100.

[0052] In an optional embodiment, the first busbar 210, second busbar 220, first interdigital electrode 230, first ground dummy finger 240, second interdigital electrode 250, second ground dummy finger 260, first floating dummy finger 270, and second floating dummy finger 280 in the interdigital transducer 200 are made of the same material. During resonator fabrication, the interdigital transducer 200 is fabricated using a common process, i.e., it is fabricated with a single monolithic photomask. This eliminates the need for complex process changes in the fabrication of the floating dummy finger; it can be formed simultaneously with the interdigital electrode and ground dummy finger simply by optimizing the photomask image. This allows for flexible performance optimization by adjusting the layout of the ground dummy finger and floating dummy finger in the interdigital transducer 200 without altering the resonator's base layer parameters, providing high engineering design flexibility and industrial application value.

[0053] Specifically, the interdigital transducer 200 can be made of metals such as aluminum, platinum, copper, gold, titanium, nickel, chromium, tungsten, silver, palladium, cobalt, and manganese.

[0054] In an optional embodiment, the shape of the first floating phasor 270 may be the same as or different from the shape of the second floating phasor 280. The shape of the first floating phasor 270 may be any of the following: rectangular, trapezoidal, rhomboid, geometric shape with rounded corners, or other irregular shape. This embodiment does not limit this, as long as it can achieve its function.

[0055] The resonator provided in this embodiment includes a piezoelectric substrate 100 and an interdigital transducer 200 disposed on the piezoelectric substrate 100. The interdigital transducer 200 includes a first busbar 210 and a second busbar 220 disposed opposite to each other. A first interdigital electrode 230 and a first grounding pseudo-finger 240 connected to the first busbar 210 are disposed between the first busbar 210 and the second busbar 220, and a second interdigital electrode 250 and a second grounding pseudo-finger 260 are connected to the second busbar 220. The first interdigital electrode 230 and the first grounding pseudo-finger 240 are arranged alternately at intervals along the extension direction of the first busbar 210. The first interdigital electrode 230 and the second grounding dummy finger 260 are arranged alternately along the extension direction of the second busbar 220; the first interdigital electrode 230 and the second grounding dummy finger 260 are arranged opposite each other; the interdigital transducer 200 also includes a first floating dummy finger 270 and a second floating dummy finger 280. The first floating dummy finger 270 is disposed between the first interdigital electrode 230 and the second grounding dummy finger 260 and is spaced apart from the first interdigital electrode 230 and the second grounding dummy finger 260. The second floating dummy finger 280 is disposed between the second interdigital electrode 250 and the first grounding dummy finger 240 and is spaced apart from the second interdigital electrode 250 and the first grounding dummy finger 240. In this embodiment, the first suspended pseudo-finger 270 and the second suspended pseudo-finger 280 are electrically suspended. When the interdigital transducer 200 is working, the first suspended pseudo-finger 270 and the second suspended pseudo-finger 280 can generate induced charges through electromechanical coupling effect, thereby forming a dynamically floating induced potential. This induced potential can automatically correct the non-uniform electric field caused by geometric abrupt changes at the ends of the first interdigital electrode 230 and the second interdigital electrode 250, and achieve "smoothing" of the electric field intensity. This can eliminate strong electric field gradients and suppress the high-order transverse parasitic modes excited by the first grounded pseudo-finger 240 and the second grounded pseudo-finger 260 due to electric field distortion from the source. Furthermore, the arrangement of the first floating pseudo-finger 270 and the second floating pseudo-finger 280 can construct a reflective interface at the edge of the acoustic aperture H. This reflective interface, as an acoustic barrier, can effectively confine the acoustic energy of the main mode in the resonator within the effective acoustic aperture H region, significantly reducing the scattering and diffraction loss of energy in the direction of the first busbar 210 and the second busbar 220, thereby improving the quality factor of the resonator.

[0056] Furthermore, the setting of the first floating pseudo-finger 270 and the second floating pseudo-finger 280 can precisely correct the boundary phase, which can destroy the constructive interference of higher-order transverse modes and the resonance conditions of parasitic modes. This effectively suppresses spurious modes in the high-frequency band above 6.5GHz, broadens the operating frequency band of the resonator in the 5G / 6G communication field, and enables it to maintain excellent electroacoustic conversion efficiency in high-frequency and high-power environments. This has a profound impact on the localization of resonators and the development of high-performance acoustic devices.

[0057] In one embodiment, such as Figure 2 As shown, a first gap W1 is included between the first floating spur finger 270 and the first interdigital electrode 230, and a second gap W2 is included between the first floating spur finger 270 and the second grounded spur finger 260; along the extending direction of the first interdigital electrode 230, the size of the first gap W1 is the same as the size of the second gap W2.

[0058] A third gap W3 is included between the second floating spur finger 280 and the second interdigital electrode 250, and a fourth gap W4 is included between the second floating spur finger 280 and the first grounding spur finger 240; along the extending direction of the second interdigital electrode 250, the dimensions of the third gap W3 and the fourth gap W4 are the same.

[0059] The first levitation spur 270 is spaced between the first interdigital electrode 230 and the second grounding spur 260. Along the Y direction, the maximum distance between the first levitation spur 270 and the first interdigital electrode 230 is the same as the maximum distance between the first levitation spur 270 and the second grounding spur 260. The second levitation spur 280 is spaced between the second interdigital electrode 250 and the first grounding spur 240. Along the Y direction, the maximum distance between the second levitation spur 280 and the second interdigital electrode 250 is the same as the maximum distance between the second levitation spur 280 and the first grounding spur 240.

[0060] In an optional embodiment, the dimensions of the first gap W1 and the third gap W3 along the Y direction may be the same or different.

[0061] In this embodiment, along the Y-direction, the size of the first gap W1 between the first floating pseudo-finger 270 and the first interdigital electrode 230 is the same as the size of the second gap W2 between the first floating pseudo-finger 270 and the second grounding pseudo-finger 260. This equal spacing ensures the balance of the induced potential at the ends of the first interdigital electrode 230 or the second grounding pseudo-finger 260, thus constructing a symmetrical acoustic reflection boundary and phase compensation band. This avoids the generation of higher-order transverse stray modes, thereby improving the quality factor of the resonator. Similarly, along the Y-direction, the size of the third gap W3 between the second floating pseudo-finger 280 and the second interdigital electrode 250 is the same as the size of the fourth gap W4 between the second floating pseudo-finger 280 and the first grounding pseudo-finger 240. This equal spacing ensures the balance of the induced potential at the ends of the second interdigital electrode 250 or the first grounding pseudo-finger 240, thus constructing a symmetrical acoustic reflection boundary and phase compensation band. This avoids the generation of higher-order transverse stray modes, thereby improving the quality factor of the resonator.

[0062] In one embodiment, the size of the first grounding dummy finger 240 is greater than or equal to 0.5 along the extending direction of the first grounding dummy finger 240. And less than or equal to 1.0 Specifically, the size of the first grounding dummy finger 240 can be 0.5. 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 Or 1.0 .

[0063] Along the extending direction of the second grounding dummy finger 260, the size of the second grounding dummy finger 260 is greater than or equal to 0.5. And less than or equal to 1.0 Specifically, the size of the second grounding dummy finger 260 can be 0.5. 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 Or 1.0 .

[0064] Understandably, along the Y direction, the maximum length of the first grounding dummy finger 240 can be set to 0.5. -1.0 Within the range. Similarly, the maximum length of the second grounding dummy finger 260 can also be set at 0.5. -1.0 Within the range.

[0065] In one specific embodiment, along the Y direction, the maximum length of the first grounding dummy finger 240 and the maximum length of the second grounding dummy finger can be the same, both being 0.75. .

[0066] In a resonator, along the Y-direction, if the length of the grounding dummy finger is too large, the sound wave will resonate at the grounding dummy finger, causing energy to concentrate at the grounding dummy finger and generating new higher-order stray emissions. If the length of the grounding dummy finger is too small, the distance between the corresponding interdigitated electrode and the busbar is too close, and charge can easily leak directly into the busbar through the gap between the grounding dummy finger and the interdigitated electrode, thus causing a decrease in the resonator's quality factor. Therefore, both excessively long and excessively short grounding dummy fingers will affect the resonator's performance. In this embodiment, it is indicated that along the Y-direction, the maximum length of both the first grounding dummy finger 240 and the second grounding dummy finger 260 can be set to 0.5. -1.0 Within this range, it avoids the first grounding dummy finger 240 and the second grounding dummy finger 260 being too long or too small, which could affect the performance of the resonator. Furthermore, users can adjust the length according to actual application requirements within 0.5... -1.0 Adjusting the lengths of the first grounding dummy finger 240 and the second grounding dummy finger 260 within a certain range can improve the practicality of the resonator.

[0067] In one embodiment, the dimension of the first gap W1 along the extending direction of the first interdigital electrode 230 is greater than or equal to 0.1. And less than or equal to 0.4 Specifically, the size of the first gap W1 can be 0.1. 0.15 0.2 0.25 0.3 0.35 Or 0.4 .

[0068] Along the extending direction of the second interdigital electrode 250, the dimension of the third gap W3 is greater than or equal to 0.1. And less than or equal to 0.4 , This represents the arrangement period of the interdigital transducers; specifically, the dimension of the third gap W3 can be 0.1. 0.15 0.2 0.25 0.3 0.35 Or 0.4 .

[0069] Along the Y direction, the minimum length of the first gap W1 can be set to 0.1. -0.4 Within its range. Similarly, the minimum length of the third gap W3 can also be set to 0.1. -0.4 Within the area it is located in.

[0070] In an optional embodiment, along the Y direction, the maximum length of the first grounding dummy finger 240 and the second grounding dummy finger 260 is fixed at 0.75. To ensure no energy leakage and to better suppress transverse modes, the minimum lengths of both the first gap W1 and the second gap W2 are 0.25. The minimum lengths of the third gap W3 and the fourth gap W4 are also 0.25. .

[0071] In this embodiment, it is indicated that the minimum length of the first gap W1, the second gap W2, the third gap W3, and the fourth gap W4 along the Y direction can be set to 0.1. -0.4 Within this range, users can adjust the frequency according to their specific application requirements (e.g., 0.1). -0.4 The minimum lengths of the first gap W1, the second gap W2, the third gap W3, and the fourth gap W4 can be flexibly adjusted within the range, thereby automatically correcting the electric field at the edges of the first interdigital electrode 230 and the second interdigital electrode 250 using the generated induced potential, in order to suppress parasitic modes and improve the quality factor of the resonator.

[0072] In one embodiment, such as Figure 3 As shown, the first floating pseudo-finger 270 includes at least two first sub-floating pseudo-fingers 271, with adjacent first sub-floating pseudo-fingers 271 spaced apart.

[0073] The second levitation pseudofinger 280 includes at least two second sub-levitation pseudofingers 281, with adjacent second sub-levitation pseudofingers spaced apart.

[0074] It is understood that at least two first sub-floating pseudo-fingers 271 are provided between the first interdigital electrode 230 and the second grounding pseudo-finger 260. Among the at least two first sub-floating pseudo-fingers 271, the first sub-floating pseudo-finger 271 closest to the first interdigital electrode 230 is spaced apart from the first interdigital electrode 230, the first sub-floating pseudo-finger 271 closest to the second grounding pseudo-finger 260 is spaced apart from the second grounding pseudo-finger 260, and any two adjacent first sub-floating pseudo-fingers 271 are spaced apart.

[0075] Similarly, at least two second sub-floating pseudo-fingers 281 are provided between the second interdigital electrode 250 and the first ground pseudo-finger 240. Among the at least two second sub-floating pseudo-fingers 281, the second sub-floating pseudo-finger 281 closest to the second interdigital electrode 250 is spaced apart from the second interdigital electrode 250, the second sub-floating pseudo-finger 281 closest to the first ground pseudo-finger 240 is spaced apart from the first ground pseudo-finger 240, and any two adjacent second sub-floating pseudo-fingers 281 are spaced apart.

[0076] In this embodiment, at least two first sub-floating pseudo-fingers 271 are provided between the first interdigital electrode 230 and the second grounding pseudo-finger 260, and at least two second sub-floating pseudo-fingers 281 are provided between the second interdigital electrode 250 and the first grounding pseudo-finger 240. This increases the number of sub-floating pseudo-fingers per unit area without increasing parasitic capacitance, achieving accurate reconstruction of the potential distribution at the edge of the sound field. This effectively resolves the contradiction between stray suppression and quality factor, resulting in higher reliability for the resonator provided in this embodiment. Furthermore, users can flexibly adjust the number of first sub-floating pseudo-fingers 271 and second sub-floating pseudo-fingers 281 according to application requirements, improving the resonator's practicality.

[0077] Please continue reading Figure 3 In one embodiment, a fifth gap W5 is included between two adjacent first sub-suspended pseudo-finger 271, and the size of the fifth gap W5 is the same as the size of the first gap W1 along the extending direction of the first interdigital electrode 230.

[0078] A sixth gap W6 is included between two adjacent second sub-suspended pseudo-finger 281. Along the extension direction of the second interdigital electrode 250, the size of the sixth gap W6 is the same as that of the third gap W3.

[0079] It is understandable that, along the Y direction, the maximum distance between two adjacent first sub-levitation spurs 271 is the same as the maximum distance between the first sub-levitation spur 271 closest to the first interdigital electrode 230 and the first interdigital electrode 230. In other words, the plurality of first sub-levitation spurs 271 disposed between the first interdigital electrode 230 and the second grounding spur 260 are equally spaced.

[0080] Similarly, along the Y direction, the maximum distance between two adjacent second sub-levitation spurs 281 is the same as the maximum distance between the second sub-levitation spur 281 near the second interdigital electrode 250 and the second interdigital electrode 250. In other words, the plurality of second sub-levitation spurs 281 disposed between the second interdigital electrode 250 and the first grounding spur 240 are equally spaced.

[0081] In this embodiment, at least two first sub-floating pseudo-fingers 271 are equally spaced between the first interdigital electrode 230 and the second ground pseudo-finger 260, and at least two second sub-floating pseudo-fingers 281 are equally spaced between the second interdigital electrode 250 and the first ground pseudo-finger 240. This can improve the suppression effect on transverse parasitic modes and reduce stray fluctuations to a greater extent, thereby improving the performance (quality factor) of the resonator.

[0082] Of course, in other examples, the size of the fifth gap W5 may also be different from the size of the first gap W1, that is, the multiple first sub-suspended spurs 271 may be set at non-equidistant intervals with the first interdigital electrode 230 and the second grounded spur 260; the size of the sixth gap W6 may also be different from the size of the third gap W3, that is, the multiple second sub-suspended spurs 281 may be set at non-equidistant intervals with the second interdigital electrode 250 and the first grounded spur 240.

[0083] In an optional embodiment, the first levitating spur 270 includes two first sub-levitating spurs 271, and the second levitating spur 280 includes two second sub-levitating spurs 281. In other words, double-density first sub-levitating spurs are arranged between the first interdigital electrode 230 and the second grounding spur 260, and double-density second sub-levitating spurs are also arranged between the second interdigital electrode 250 and the first grounding spur 240.

[0084] Of course, in other examples, the first floating pseudo-finger 270 may include more first sub-floating pseudo-fingers 271, and the second floating pseudo-finger 280 may include multiple second sub-floating pseudo-fingers 281, such as three, four, or more. When the first floating pseudo-finger 270 includes more than two first sub-floating pseudo-fingers 271, the size of the gap between adjacent first sub-floating pseudo-fingers 271 may not be exactly the same; similarly, when the second floating pseudo-finger 280 includes more than two second sub-floating pseudo-fingers 281, the size of the gap between adjacent second sub-floating pseudo-fingers 281 may not be exactly the same.

[0085] In an optional embodiment, simulation comparisons of the admittance and conductance of the resonator as a function of frequency under different structures are shown below. Figure 4 As shown, to clearly compare the lateral spurious suppression effects under different results, Figure 4 The simulation curves were shifted along the vertical axis (admittance and conductance). Specifically, based on a traditional grounding structure, i.e., a structure with the busbar and grounding dummy finger spaced apart, a data line with a floating dummy finger structure spaced apart between the busbar and grounding dummy finger was shifted upwards by 100 dB. A data line with two sub-floating dummy fingers spaced apart between the busbar and grounding dummy finger, i.e., a double-density floating structure, was further shifted upwards by 100 dB based on the existing floating dummy finger structure. This achieved a vertically equidistant arrangement of the three sets of data curves, facilitating observation of the local fluctuations of each structure at the high-frequency side of the main resonance peak. Figure 4 As can be seen, the structure with spaced grounding pseudo-finger spacing in the related technology exhibits a large number of stray peaks on the high-frequency side of the main resonance peak (6.55 GHz-6.65 GHz), while the double-density suspension structure with equal spacing and a spacing of 0.25... At this time, the admittance curve is extremely smooth, and the corresponding conductance curve (dashed line) is also relatively smooth on the high-frequency side of the main resonance peak. The transverse spurious mode is completely suppressed and effectively eliminated at the energy conversion level.

[0086] The simulation results show the quality factor of the resonator under different structures as follows: Figure 5 As shown, from Figure 5 As can be seen, the peak Q values ​​of different structures all appear around 6.525 GHz. The Q value decreases in structures with grounding spurious intervals, while the double-density suspension structure achieves the best performance, with a peak Q value of approximately 2.35 × 10⁻⁶. 5 .

[0087] The simulation results demonstrate the effect of horizontal movement of different sub-levitation spur fingers on the admittance and conductance curves of the resonator in a double-density levitation structure. Figure 6 As shown.

[0088] like Figure 6As shown in curve (b), the sub-suspended pseudofinite fingers are evenly spaced (0.25). The distances between the first interdigital electrode 230 and the first sub-levitation spur 271, the distances between two adjacent first sub-levitation spurs 271, and the distance between the second grounding spur 260 and the first sub-levitation spur 271 are all equal, and all are 0.25. In the ideal layout, the admittance and conductance curves are extremely smooth on the high-frequency side of the dominant mode, with no obvious stray fluctuations, achieving optimal suppression of transverse parasitic modes. With the sub-levitation pseudo-fingers not evenly spaced, i.e. along the Y direction, the first sub-levitation pseudo-finger 271, which is closer to the first ground pseudo-finger 240, is moved (leftward) by 0.2 degrees away from the first ground pseudo-finger 240. The second sub-suspended pseudo-finger 281, which is closer to the second grounding pseudo-finger 260, is moved (leftward) by 0.2 degrees. This would break the symmetrical spacing, causing a sharp decrease in the spacing between adjacent first sub-floating pseudo-finger 271 and adjacent second sub-floating pseudo-finger 281, while the spacing between the first sub-floating pseudo-finger 271 and the first grounding pseudo-finger 240, and the spacing between the second sub-floating pseudo-finger 281 and the second grounding pseudo-finger 260, would increase accordingly. Figure 6 As shown in curve (a), due to the severe imbalance of local coupling boundary conditions, multiple strong transverse parasitic resonance peaks are re-excited on the high-frequency side of the main resonance peak, thus destroying the spectral purity. Similarly, with the sub-suspended pseudo-fingers not evenly spaced, i.e. along the Y direction, the first sub-suspended pseudo-finger 271, which is closer to the first grounded pseudo-finger 240, is moved (shifted to the right) by 0.2 towards the first grounded pseudo-finger 240. The second sub-suspended pseudo-finger 281, which is closer to the second grounding pseudo-finger 260, is moved (moved to the right) by 0.2 in the direction closer to the second grounding pseudo-finger 260. .like Figure 6 As shown in curve (c), this asymmetric boundary condition also disrupts the originally uniform phase compensation mechanism, leading to the reappearance of significant transverse stray modes. Figure 6 As can be seen, when the sub-suspended pseudo-finger is set at equal intervals, the most perfect symmetrical acoustic reflection boundary can be constructed at the edge of the acoustic aperture H.

[0089] In one embodiment, the piezoelectric substrate 100 includes a substrate and a piezoelectric layer disposed on the substrate.

[0090] It is understood that the piezoelectric substrate 100 is a piezoelectric-on-insulator (POI) composite substrate composed of a substrate and a piezoelectric layer. The substrate serves as a support substrate, supporting the piezoelectric layer and interdigital transducer 200 disposed thereon. The substrate material can be silicon carbide, high-resistivity silicon, quartz, glass, etc. The piezoelectric layer is used to perform the mutual conversion between electrical signals and surface acoustic waves, thereby enhancing the surface acoustic wave of the interdigital transducer 200. The piezoelectric layer material can be lithium tantalate, lithium niobate, or a piezoelectric thin film. This embodiment does not limit the specific materials of the substrate and piezoelectric layer, as long as their functions can be achieved.

[0091] In this embodiment, the piezoelectric substrate 100 includes a substrate and a piezoelectric layer. Such a piezoelectric substrate 100 has a simple structure and is easy to implement, which can improve the practicality of the resonator.

[0092] In an optional embodiment, the piezoelectric substrate 100 in the resonator includes a piezoelectric layer, which is 42° lithium tantalate. For example: 42° YX-cut Lithium Tantalate Normal Surface Acoustic Wave (42°LT Normal SAW).

[0093] In one embodiment, such as Figure 7 As shown, the resonator also includes a reflector 300, which is disposed on the piezoelectric substrate 100.

[0094] Along the extension direction of the first busbar 210 in the interdigital transducer 200, the reflector 300 is disposed on opposite sides of the interdigital transducer 200.

[0095] Understandably, reflectors 300 are provided on both sides of the interdigital transducer 200 in the X direction. The reflectors 300 are used to reflect surface acoustic waves to form a stable standing wave between the interdigital transducers 200, thereby achieving resonance.

[0096] In an optional embodiment, such as Figure 3 As shown, reflector 300 is a short-circuit grid array composed of multiple parallel metal strips. The material of reflector 300 is the same as that of interdigital transducer 200, and they are fabricated using the same process, that is, they are fabricated simultaneously using the same photomask.

[0097] In this embodiment, by providing reflectors on both sides of the interdigital transducer 200, the energy constraint can be improved, the quality factor of the resonator can be increased, and the transverse mode and stray response can be suppressed, thereby improving the performance of the resonator.

[0098] One embodiment of this application provides a filter that includes a resonator as provided in the above embodiment.

[0099] The filter provided in this application includes the resonator provided in the above embodiments, and thus the filter has all the beneficial effects of the resonator, which will not be repeated here.

[0100] One embodiment of this application provides an electronic device that includes a filter as provided in the above embodiments.

[0101] Alternatively, the electronic device can be a variety of devices including radio frequency front-ends, such as mobile communication terminals: smartphones, wearable devices (smartwatches / wristbands, etc.), physical network devices: smart furniture (smart speakers, cameras, air conditioners, etc.), industrial physical networks, vehicle networks, etc., and communication infrastructure devices: base stations, distributed antenna systems, etc.

[0102] The electronic device provided in this application includes a filter, and thus the electronic device has all the beneficial effects of a filter, which will not be elaborated here.

[0103] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0104] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A resonator, characterized in that, The resonator includes: a piezoelectric substrate and an interdigital transducer disposed on the piezoelectric substrate; The interdigital transducer includes a first busbar and a second busbar disposed opposite to each other. A first interdigital electrode and a first grounding dummy finger are disposed between the first busbar and the second busbar, and a second interdigital electrode and a second grounding dummy finger are disposed between the first busbar and the second busbar. The first interdigital electrode and the first grounding dummy finger are arranged alternately at intervals along the extension direction of the first busbar, and the second interdigital electrode and the second grounding dummy finger are arranged alternately at intervals along the extension direction of the second busbar. The first interdigital electrode and the second grounding dummy finger are disposed opposite to each other, and the second interdigital electrode and the first grounding dummy finger are disposed opposite to each other. The interdigital transducer further includes a first suspended pseudo-finger and a second suspended pseudo-finger. The first suspended pseudo-finger is disposed between the first interdigital electrode and the second grounded pseudo-finger, and is spaced apart from the first interdigital electrode and the second grounded pseudo-finger. The second suspended pseudo-finger is disposed between the second interdigital electrode and the first grounded pseudo-finger, and is spaced apart from the second interdigital electrode and the first grounded pseudo-finger.

2. The resonator according to claim 1, characterized in that, A first gap is included between the first suspended spur and the first interdigital electrode, and a second gap is included between the first suspended spur and the second grounded spur; along the extending direction of the first interdigital electrode, the size of the first gap and the size of the second gap are the same; A third gap is included between the second suspended spur and the second interdigital electrode, and a fourth gap is included between the second suspended spur and the first grounded spur; the size of the third gap is the same as the size of the fourth gap along the extending direction of the second interdigital electrode.

3. The resonator according to claim 2, characterized in that, Along the extending direction of the first interdigitated electrode, the dimension of the first gap is greater than or equal to 0.

1. And less than or equal to 0.4 ; Along the extending direction of the second interdigitated electrode, the dimension of the third gap is greater than or equal to 0.

1. And less than or equal to 0.4 , The arrangement period of the interdigital transducers is denoted as .

4. The resonator according to claim 2, characterized in that, The first floating pseudofinger includes at least two first sub-floating pseudofingers, with adjacent first sub-floating pseudofingers spaced apart; The second floating pseudofinger includes at least two second sub-floating pseudofingers, with adjacent second sub-floating pseudofingers spaced apart.

5. The resonator according to claim 4, characterized in that, A fifth gap is included between two adjacent first sub-suspended prosthetic fingers along the extension direction of the first interdigital electrode, and the size of the fifth gap is the same as the size of the first gap; A sixth gap is included between two adjacent second sub-suspended prosthetic fingers, along the extension direction of the second interdigital electrode, and the size of the sixth gap is the same as that of the third gap.

6. The resonator according to any one of claims 1-5, characterized in that, Along the extending direction of the first grounding dummy finger, the size of the first grounding dummy finger is greater than or equal to 0.

5. And less than or equal to 1.0 ; Along the extending direction of the second grounding dummy finger, the size of the second grounding dummy finger is greater than or equal to 0.

5. And less than or equal to 1.0 .

7. The resonator according to any one of claims 1-5, characterized in that, The piezoelectric substrate includes a substrate and a piezoelectric layer, wherein the piezoelectric layer is disposed on the substrate.

8. The resonator according to any one of claims 1-5, characterized in that, The resonator further includes a reflector disposed on the piezoelectric substrate; Along the extension direction of the first busbar in the interdigital transducer, the reflector is disposed on opposite sides of the interdigital transducer.

9. A filter, characterized in that, Includes the resonator as described in any one of claims 1-8.

10. An electronic device, characterized in that, Includes the filter as described in claim 9.

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