Dual-port surface acoustic wave resonator

Abstract

The utility model discloses a dual-port surface acoustic wave resonator comprising a piezoelectric substrate, the upper end surface of the piezoelectric substrate is provided with a plurality of grooves I and grooves II which are alternately arranged in parallel at intervals along the left and right length directions, and the length directions of the grooves I and the grooves II are consistent with the width direction of the piezoelectric substrate. A plurality of interdigital electrodes on the first interdigital transducer are correspondingly embedded and fixedly arranged in the first groove, a plurality of interdigital electrodes on the second interdigital transducer are correspondingly embedded and fixedly arranged in the second groove, and the piezoelectric film is laid on the upper end face of the piezoelectric substrate. Acoustic surface waves are more concentrated on the interface between the piezoelectric substrate and the piezoelectric film in the propagation process, interference and loss caused by diffusion of energy towards other directions are reduced, the energy utilization efficiency is improved, and the dual-port surface acoustic wave resonator has the advantages that under the condition that the input energy is the same, the surface acoustic wave resonator can be applied to the surface acoustic wave resonator. Stronger signals can be output, the overall performance of the resonator is improved, and stable performance output can be kept in different working environments.

Description

Technical Field

[0001] This utility model relates to the field of surface acoustic wave resonator technology, specifically to a two-port surface acoustic wave resonator. Background Technology

[0002] Surface acoustic wave (SAW) devices have been widely used in many fields such as electronic communication technology, microfluidics, and sensors due to their unique advantages. With the deepening research and development of piezoelectric thin film materials and the continuous improvement of fabrication processes, researchers are focusing on exploring SAW devices based on layered piezoelectric thin film structures, aiming to create SAW devices with high frequency, high electromechanical coupling coefficient, and high quality factor.

[0003] Conventional methods for increasing the operating frequency of SAW devices typically include using high-velocity substrate materials or shortening the SAW wavelength. However, these methods have significant limitations. On the one hand, they are constrained by the inherent acoustic velocity characteristics of the materials themselves; on the other hand, the fabrication process also limits their effectiveness, making further breakthroughs difficult. Interdigital transducers (IDTs), as key components for exciting SAW devices, consist of comb-shaped metal electrodes arranged in an alternating pattern on the surface of a piezoelectric material. The operating frequency of a SAW device is closely related to the width of the IDT interdigital electrodes; that is, the thinner the interdigital electrodes, the higher the device operating frequency. Therefore, in recent years, fabricating high-resolution interdigital electrodes has become one of the core approaches to fabricating high-frequency SAW devices. However, due to the optical diffraction limit, traditional photolithography processes are increasingly inadequate for meeting the requirements of high-resolution, low-cost, and non-standard silicon substrates for high-frequency SAW devices. In recent years, research on optimizing SAW device performance from the perspective of interdigital electrodes has been relatively limited, and further research is urgently needed.

[0004] Existing two-port surface acoustic wave (SAW) resonators mostly employ a rectangular cross-section for the interdigital electrodes on their interdigital transducers, with several comb-shaped interdigital electrodes laid flat on the upper surface of a piezoelectric substrate. In practical operation, this structure causes significant energy dissipation as the SAW propagates towards the ground, drastically reducing energy utilization efficiency. Simultaneously, the relatively long reflection distance of the SAW generated by the rectangular interdigital electrodes increases signal transmission delay, thus affecting the overall response speed of the two-port SAW resonator and failing to meet current demands for efficient and fast-response electronic devices. Furthermore, in pursuit of higher operating frequencies and smaller device sizes, past research has often focused on fabricating narrower interdigital electrodes. However, this not only significantly increases the difficulty and cost of fabrication but also makes the interdigital electrodes highly susceptible to high-temperature melting and fatigue fracture under high-frequency vibration, significantly increasing the failure rate of SAW devices. Although some current research has shifted towards high-performance composite piezoelectric thin film materials in an attempt to improve the performance of SAW devices, relying solely on material optimization remains limited in its effectiveness in addressing the severe energy dissipation and slow response speed of surface acoustic waves. Therefore, this invention proposes a novel two-port surface acoustic wave resonator to solve the aforementioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a two-port surface acoustic wave (SAW) resonator. By embedding several interdigital electrodes on the interdigital transducer into the grooves on the upper surface of the piezoelectric substrate, the SAW waves are concentrated more at the interface between the piezoelectric substrate and the piezoelectric film during propagation. This reduces interference and losses caused by energy diffusion in other directions, effectively reducing energy dissipation and improving energy utilization efficiency. As a result, the two-port SAW resonator of this invention can output a stronger signal under the same input energy, improving the overall performance of the resonator. This allows the two-port SAW resonator of this invention to maintain stable performance output under different working environments, providing solid technical support for its application in a wider range of fields.

[0006] To achieve the above objectives, the technical solution of this utility model is to design a dual-port surface acoustic wave resonator, including a piezoelectric substrate, an interdigital transducer I, an interdigital transducer II, and a piezoelectric thin film. The upper surface of the piezoelectric substrate has several parallel and alternating grooves I and II spaced apart along the left-right length direction. The length directions of both groove I and groove II are consistent with the width direction of the piezoelectric substrate. Several interdigital electrodes on interdigital transducer I are correspondingly embedded and fixed inside groove I on the upper surface of the piezoelectric substrate. Similarly, several interdigital electrodes on interdigital transducer II are correspondingly embedded and fixed inside groove II on the upper surface of the piezoelectric substrate. The piezoelectric thin film is deposited on the upper surface of the piezoelectric substrate.

[0007] This invention discloses a two-port surface acoustic wave (SAW) resonator. By embedding several interdigital electrodes on an interdigital transducer into grooves on the upper surface of a piezoelectric substrate, the SAW waves are concentrated more at the interface between the piezoelectric substrate and the piezoelectric film during propagation. This reduces interference and losses caused by energy diffusion in other directions, effectively reducing energy dissipation and improving energy utilization efficiency. As a result, this invention enables the two-port SAW resonator to output a stronger signal under the same input energy, improving the overall performance of the resonator. This allows the two-port SAW resonator to maintain stable performance output under different operating environments, providing solid technical support for its application in a wider range of fields.

[0008] A preferred technical solution is that the cross-sections of both groove one and groove two are parallelogram structures, with a set of opposite sides of the parallelogram structure located in the horizontal direction and an acute angle α between a set of adjacent sides of 30-60°. The inclination directions of groove one and groove two are opposite to each other. Both groove one and groove two are designed as inclined groove structures with their openings facing upwards, and their inclination directions are opposite to each other, significantly shortening the reflection distance of surface acoustic waves inside the resonator. This allows surface acoustic waves to complete the reflection and propagation process more quickly, thereby greatly improving the response speed of the dual-port surface acoustic wave resonator of this invention. In practical applications, such as high-speed communication signal processing, the dual-port surface acoustic wave resonator of this invention can respond to input signals more quickly, effectively improving signal processing efficiency and accuracy.

[0009] A further preferred technical solution is that the acute angle α between a set of adjacent sides of the parallelogram structure is 45°. The grooves one and two in this structural design minimize the reflection distance of the surface acoustic wave inside the resonator, thereby enabling the surface acoustic wave to complete the reflection and propagation process more quickly, further improving the response speed of the dual-port surface acoustic wave resonator of this invention.

[0010] A further preferred technical solution includes that the front end of the first groove communicates with the front face of the piezoelectric substrate, and the rear end of the second groove communicates with the rear face of the piezoelectric substrate. The first interdigital transducer further includes a busbar connecting the upper sides of the front ends of several interdigital electrodes, and the second interdigital transducer further includes a busbar connecting the upper sides of the rear ends of several interdigital electrodes. The busbar on the first interdigital transducer has a port extending outwards from the front side of the piezoelectric substrate, and the busbar on the second interdigital transducer has a port extending outwards from the rear side of the piezoelectric substrate. The interdigital transducer structure is ingeniously and rationally designed, ensuring convenient connection for signal input and output.

[0011] A further preferred technical solution includes the following: the dimensions of both groove one and groove two are a depth d1 = 4-6 μm and a width d2 = 2-3 μm; the distance between two adjacent groove one or two adjacent groove two is d3 = 6-9 μm; the length L along the left-right direction of the piezoelectric substrate is 350-400 μm, the width W along the front-back direction is 12-13 μm, and the height D ≥ 4d1; and the lengths of both groove one and groove two are d4 ≤ 4 / 5W. The ingenious and reasonable design of the dimensions of the piezoelectric substrate, groove one, and groove two ensures the successful fabrication and implementation of this novel dual-port surface acoustic wave resonator, meeting the needs of various application scenarios. Surface acoustic waves experience energy dissipation during longitudinal propagation; this structural design largely avoids longitudinal propagation of surface acoustic waves, ensuring that their main energy is concentrated at the interface between the piezoelectric film and the piezoelectric substrate, further improving the response speed of this novel dual-port surface acoustic wave resonator, reducing energy loss, and enhancing signal strength.

[0012] To ensure sufficient output signal strength of the dual-port surface acoustic wave resonator of this invention, a further preferred technical solution is that the sum of the number of groove one and groove two is ≥100.

[0013] A further preferred technical solution is that the piezoelectric substrate is made of silicon, diamond, or glass; the interdigital transducers one and two are both made of aluminum or copper; and the piezoelectric thin film is made of zinc oxide, lithium niobate, lithium tantalate, or lanthanum gallium germanate. This provides a wide range of material choices and good applicability.

[0014] The advantages and beneficial effects of this utility model are as follows:

[0015] 1. This utility model discloses a two-port surface acoustic wave resonator. By embedding several interdigital electrodes on an interdigital transducer into the grooves on the upper surface of a piezoelectric substrate, the surface acoustic wave is concentrated more at the interface between the piezoelectric substrate and the piezoelectric film during propagation. This reduces interference and loss caused by energy diffusion in other directions, thereby effectively reducing energy dissipation and improving energy utilization efficiency. As a result, the two-port surface acoustic wave resonator of this utility model can output a stronger signal under the same input energy, improving the overall performance of the resonator. This allows the two-port surface acoustic wave resonator of this utility model to maintain stable performance output under different working environments, providing solid technical support for its application in a wider range of fields.

[0016] 2. The cross-sections of both groove one and groove two are parallelogram structures. A set of opposite sides of the parallelogram structure are horizontal, and the acute angle α between a set of adjacent sides is 30–60°. The inclination directions of groove one and groove two are opposite. Both groove one and groove two are designed as inclined groove structures with their openings facing upwards, and their inclination directions are opposite, significantly shortening the reflection distance of the surface acoustic wave (SAW) inside the resonator. This allows the SAW to complete the reflection and propagation process more quickly, thereby greatly improving the response speed of the dual-port SAW resonator of this invention. In practical applications, such as high-speed communication signal processing, the dual-port SAW resonator of this invention can respond to input signals more quickly, effectively improving signal processing efficiency and accuracy.

[0017] 3. The dimensions of groove one and groove two are both depth d1 = 4-6 μm and width d2 = 2-3 μm. The distance between two adjacent grooves 1 or 2 is d3 = 6-9 μm. The piezoelectric substrate has a length L = 350-400 μm in the left-right direction, a width W = 12-13 μm in the front-back direction, and a height D ≥ 4d1. Furthermore, the lengths of groove one and groove two are both d4 ≤ 4 / 5W. The ingenious and reasonable design of the dimensions of the piezoelectric substrate, groove one, and groove two ensures the smooth fabrication and implementation of this utility model's dual-port surface acoustic wave resonator, meeting the usage requirements of various application scenarios. Surface acoustic waves generate energy dissipation during longitudinal propagation. This size and structural design can largely avoid the longitudinal propagation of surface acoustic waves, ensuring that its main energy is concentrated at the interface between the piezoelectric film and the piezoelectric substrate, further improving the response speed of this utility model's dual-port surface acoustic wave resonator, reducing its energy loss, and enhancing signal strength. Attached Figure Description

[0018] Figure 1 This is a top-view perspective view of a dual-port surface acoustic wave resonator according to this utility model;

[0019] Figure 2 This is an exploded view of a two-port surface acoustic wave resonator according to this utility model;

[0020] Figure 3 This is a 3D view of interdigital transducer one;

[0021] Figure 4 This is a top-view 3D view of the piezoelectric substrate;

[0022] Figure 5 This is a front view of the piezoelectric substrate;

[0023] Figure 6 This is an assembly diagram of interdigital transducer one and interdigital transducer two on a piezoelectric substrate.

[0024] In the figure: 1. Piezoelectric substrate; 2. Interdigital transducer one; 3. Interdigital transducer two; 4. Piezoelectric thin film; 1-1. Groove one; 1-2. Groove two; a. Interdigital electrode; b. Busbar; c. Port. Detailed Implementation

[0025] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0026] Example

[0027] like Figures 1-6 As shown, this utility model is a two-port surface acoustic wave resonator, including a piezoelectric substrate 1, an interdigital transducer 2, an interdigital transducer 3, and a piezoelectric film 4. The upper surface of the piezoelectric substrate 1 is provided with a plurality of parallel and alternating grooves 1-1 and 1-2 along the left and right length directions, and the length directions of the grooves 1-1 and 1-2 are consistent with the width direction of the piezoelectric substrate 1. A plurality of interdigital electrodes a on the interdigital transducer 2 are embedded and fixed in the grooves 1-1 on the upper surface of the piezoelectric substrate 1, and a plurality of interdigital electrodes a on the interdigital transducer 3 are embedded and fixed in the grooves 1-2 on the upper surface of the piezoelectric substrate 1. The piezoelectric film 4 is laid on the upper surface of the piezoelectric substrate 1.

[0028] Preferably, the cross-sections of both groove 1-1 and groove 1-2 are parallelogram structures, and a set of opposite sides of the parallelogram structure are located in the horizontal direction, the acute angle α between a set of adjacent sides is 30 to 60°, and the inclination directions of groove 1-1 and groove 1-2 are opposite to each other.

[0029] More preferably, the acute angle α between a set of adjacent sides of the parallelogram structure is 45°.

[0030] More preferably, the front end of the first groove 1-1 communicates with the front end face of the piezoelectric substrate 1, the rear end of the second groove 1-2 communicates with the rear end face of the piezoelectric substrate 1, the first interdigital transducer 2 further includes a busbar b that connects the upper sides of the front ends of a plurality of interdigital electrodes a together, the second interdigital transducer 3 further includes a busbar b that connects the upper sides of the rear ends of a plurality of interdigital electrodes a together, the busbar b on the first interdigital transducer 2 has a port c extending outward to the front side of the piezoelectric substrate 1, and the busbar b on the second interdigital transducer 3 has a port c extending outward to the rear side of the piezoelectric substrate 1.

[0031] More preferably, the dimensions of the first groove 1-1 and the second groove 1-2 are both depth d1 = 4~6μm and width d2 = 2~3μm, the distance between two adjacent first grooves 1-1 or two adjacent second grooves 1-2 is d3 = 6~9μm, the length of the piezoelectric substrate 1 along the left-right direction is L = 350~400μm, the width along the front-back direction is W = 12~13μm, the height is D≥4d1, and the length of the first groove 1-1 and the length of the second groove 1-2 are both d4≤4 / 5W.

[0032] More preferably, the sum of the number of groove 1-1 and groove 1-2 is ≥100.

[0033] More preferably, the piezoelectric substrate 1 is made of silicon, diamond, or glass; the interdigital transducer 1 2 and interdigital transducer 2 3 are both made of aluminum or copper; and the piezoelectric thin film 4 is made of zinc oxide, lithium niobate, lithium tantalate, or gallium lanthanum germanate.

[0034] The manufacturing principle of a two-port surface acoustic wave resonator according to this utility model:

[0035] Grooves 1-1 and 1-2 are formed on the upper surface of the piezoelectric substrate 1; then molten aluminum or molten copper is poured onto the upper surface of the piezoelectric substrate 1, and after cooling, an aluminum layer or copper layer is formed; corresponding interdigital transducers 2 and 3 are formed on the aluminum layer or copper layer by photolithography; finally, a piezoelectric thin film 4 of a certain thickness is sprayed onto the upper surface of the piezoelectric substrate 1.

[0036] This invention discloses a two-port surface acoustic wave (SAW) resonator. By embedding several interdigital electrodes on an interdigital transducer into grooves on the upper surface of a piezoelectric substrate, the SAW waves are concentrated more at the interface between the piezoelectric substrate and the piezoelectric film during propagation. This reduces interference and losses caused by energy diffusion in other directions, effectively reducing energy dissipation and improving energy utilization efficiency. As a result, this invention enables the two-port SAW resonator to output a stronger signal under the same input energy, improving the overall performance of the resonator. This allows the two-port SAW resonator to maintain stable performance output under different operating environments, providing solid technical support for its application in a wider range of fields.

[0037] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A dual-port surface acoustic wave resonator, characterized by, The piezoelectric substrate (1) is provided with a plurality of parallel and alternate grooves (1-1) and (1-2) on the upper surface, the length direction of the grooves (1-1) and (1-2) is consistent with the width direction of the piezoelectric substrate (1), the intercalated interdigital electrodes (a) of the interdigital transducer (2) are arranged in the grooves (1-1) of the piezoelectric substrate (1), the intercalated interdigital electrodes (a) of the interdigital transducer (3) are arranged in the grooves (1-2) of the piezoelectric substrate (1), and the piezoelectric film (4) is arranged on the upper surface of the piezoelectric substrate (1).

2. The dual-port surface acoustic wave resonator of claim 1, wherein, The cross section of the grooves (1-1) and (1-2) is parallelogram structure, the acute angle α between the adjacent sides of the parallelogram structure is 30-60°, and the inclined directions of the grooves (1-1) and (1-2) are opposite.

3. The dual-port surface acoustic wave resonator of claim 2, wherein, The acute angle α between the adjacent sides of the parallelogram structure is 45°.

4. The dual-port surface acoustic wave resonator of claim 3, wherein, The front end of the groove (1-1) is connected with the front surface of the piezoelectric substrate (1), the rear end of the groove (1-2) is connected with the rear surface of the piezoelectric substrate (1), the interdigital transducer (2) further comprises a bus bar (b) connecting the upper sides of the front end of the intercalated interdigital electrodes (a), the interdigital transducer (3) further comprises a bus bar (b) connecting the upper sides of the rear end of the intercalated interdigital electrodes (a), the bus bar (b) of the interdigital transducer (2) has a port (c) extending to the outside of the front surface of the piezoelectric substrate (1), and the bus bar (b) of the interdigital transducer (3) has a port (c) extending to the outside of the rear surface of the piezoelectric substrate (1).

5. The dual-port surface acoustic wave resonator of claim 4, wherein, The size of the grooves (1-1) and (1-2) is depth d1=4-6μm, width d2=2-3μm, the distance between the adjacent two grooves (1-1) or (1-2) is d3=6-9μm, the length of the piezoelectric substrate (1) in the left-right direction is L=350-400μm, the width of the piezoelectric substrate (1) in the front-rear direction is W=12-13μm, the height of the piezoelectric substrate (1) is D≥4d1, and the length of the grooves (1-1) and (1-2) is d4≤4 / 5W.

6. The dual-port surface acoustic wave resonator of claim 5, wherein, The number of the grooves (1-1) and (1-2) is greater than or equal to 100.

7. The dual-port surface acoustic wave resonator according to any one of claims 1 to 6, wherein The material of the piezoelectric substrate (1) is one of silicon, diamond and glass, the material of the interdigital transducer (2) and (3) is one of aluminum and copper, and the material of the piezoelectric film (4) is one of zinc oxide, lithium niobate, lithium tantalate and gallium lanthanum germanate.

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