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Resonator structure design for high-performance surface acoustic wave filter

A surface acoustic wave and structural design technology, applied in the direction of instruments, calculations, special data processing applications, etc., to achieve the effects of structural optimization design suppression, high electromechanical coupling coefficient, and good frequency and temperature stability

Inactive Publication Date: 2018-05-15
天通瑞宏科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the existing technical literature related to the propagation characteristics of surface acoustic waves on such layered structures and the optimal design of structural parameters have not been reported, which is a key issue that needs to be solved urgently in the development of high-performance surface acoustic wave filters for different application requirements.

Method used

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  • Resonator structure design for high-performance surface acoustic wave filter
  • Resonator structure design for high-performance surface acoustic wave filter
  • Resonator structure design for high-performance surface acoustic wave filter

Examples

Experimental program
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Effect test

Embodiment 1

[0032] A resonator structure (1) for high-performance SAW filters, such as figure 1 (c), using single crystal Si substrate (2), multilayer thin film structure (7), YX-θ LiTaO 3 The piezoelectric film (5), the interdigitated electrode IDT mainly composed of Cu electrodes, the reflective grid (6) and the like are stacked and arranged sequentially from bottom to top. The multi-layer film structure (7) is formed by alternately depositing high acoustic impedance films (3) and low acoustic impedance films (4), such as figure 1 (b) shown.

[0033] In this embodiment, the thickness of the single crystal Si substrate is greater than or equal to 2 lambda , the thickness of high acoustic impedance film and low acoustic impedance film is 0.25 lambda AlN and SiO 2 film. YX-θ LiTaO 3 The piezoelectric film thickness is 0.2 lambda, the Euler angle is θ=42 o , the electrode thickness range is 0.01 lambda ~0.08 lambda .

[0034] figure 2 and image 3 Respectively, the electrome...

Embodiment 2

[0036] In this embodiment, the electrode thickness is 0.02 lambda , YX-θ LiTaO 3 The piezoelectric film thickness range is 0.1 lambda ~2 lambda , all the other are with embodiment 1.

[0037] Figure 4 and Figure 5 Respectively, the surface acoustic wave resonator structure in this embodiment is in different YX-θ LiTaO 3 Electromechanical coupling coefficients and phase velocity curves at resonance and antiresonance for the next-order Rayleigh wave and second-order horizontal shear wave through the thickness of the piezoelectric film. Such as Figure 4 As shown in , the electromechanical coupling coefficient of the horizontal shear wave first increases and then decreases with the increase of the film thickness. In YX-θ LiTaO 3 The piezoelectric film thickness is 0.2 lambda When , the maximum value of the electromechanical coupling coefficient is 12%. However, the electromechanical coupling coefficient of the Rayleigh wave is very small (less than 0.17%) and increases...

Embodiment 3

[0039] In this embodiment, the electrode thickness is 0.02 lambda , YX-θ LiTaO 3 The piezoelectric film thickness range is 0.2 lambda , the Euler angle is θ and the range is 0 o ~180 o , all the other are with embodiment 1.

[0040] Figure 6 and Figure 7 Respectively, the electromechanical coupling coefficients of the SAW resonator structure in this embodiment at different Euler angles θ for the next-order Rayleigh wave and the second-order horizontal shear wave, and the phase velocity curves at resonance and anti-resonance. Such as Figure 6 As shown in , when the Euler angle θ is at 0 o ~60 o Inside, the electromechanical coupling coefficient of the horizontal shear wave is 8.7%~12%; the Euler angle is 25 o When , the electromechanical coupling coefficient takes the largest value: 13.2%; the Euler angle is 120 o , the electromechanical coupling coefficient is almost zero. The electromechanical coupling coefficient of the Rayleigh wave first increases and the...

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Abstract

The invention provides a resonator structure design for a high-performance surface acoustic wave filter, which can be used for effectively inhibiting the clutter response caused by rayleigh waves andbody waves. The resonator structure (1) of the high-performance surface acoustic wave filter comprises a monocrystal Si substrate (2), a multi-layer film structure (7), a YX-theta LiTaO3 piezoelectricfilm (5), an interdigital electrode IDT mainly dominated by Al or Cu electrodes, a reflecting grating (6) and the like which are sequentially overlaid from bottom to top, wherein the multi-layer filmstructure (7) is formed by alternated sedimentation of high acoustic impedance films (3) and low acoustic impedance films (4); and the resonator structure (1) of the high-performance surface acousticwave filter has an optimized formula in the following way: the euler angle theta and standard thickness of the YX-theta LiTaO3 piezoelectric film respectively meet the following relationships: thetais more than or equal to 0 and less than or equal to 60, and hLT is more than or equal to 0.1 time lambda and less than or equal to 0.5 time lambda.

Description

technical field [0001] The invention relates to the structural design of a resonator used for a surface acoustic wave device of a mobile communication radio frequency front end, in particular to a structural design of a resonator used for a high-performance surface acoustic wave filter. Background technique [0002] Surface acoustic wave (SAW) filters are indispensable key components in mobile phone radio frequency (RF) front-end applications due to their small size, high performance, and reasonable cost. With the popularization of smart phones and video services, the increase of mobile data traffic and the high-speed data transmission rate of mobile terminals have become urgent demands in current mobile communications. In this case, for filter components, in addition to lower insertion loss and higher attenuation, it is necessary to further improve the rectangularization of the passband shape and the steepness of the transition band, which requires the SAW for the filter R...

Claims

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Application Information

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IPC IPC(8): H03H9/25G06F17/50
CPCH03H9/25G06F30/00
Inventor 陈景吴长春廖庆嵩宋磊
Owner 天通瑞宏科技有限公司
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