17% relative bandwidth low-loss surface acoustic filter and preparation method thereof
A sound surface filter and low loss technology, applied in the field of sound surface filter design and preparation, can solve the problems of large volume and poor squareness of LC filters, and achieve the effects of small volume, wide bandwidth and low loss
Inactive Publication Date: 2017-06-13
北京中科飞鸿科技股份有限公司
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Problems solved by technology
Therefore, LC filters are mainly used to meet the requirements of broadband and low loss indicators, but LC filters are large in size, usually 25mm*9mm or 15mm*8mm, with poor rectangularity and need to be repeatedly debugged
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[0039] The overall structure of the 17% relative bandwidth low-loss SAW filter is as follows figure 1 Shown:
[0040] Comprising a wafer material 101, a trapezoidal acoustic surface transducer 102 of a copper grid array, and a sound-absorbing layer 103 coated on the surface,
[0041] The specific requirements are as follows:
[0042] (1) The wafer material is 15°YX-LiNbO 3 , the thickness of the wafer is 0.40-0.65 μm, and the back is roughened with 360-1000.
[0043] (2) The design structure of the trapezoidal SAW transducer 102 is a trapezoidal design structure, and its structure diagram is as follows figure 2 shown. For the trapezoidal SAW transducer 102, the number of stages of resonators and the combined layout method can be selected according to specific index requirements and packaging methods.
[0044] (3) The functional film is a copper film, and the film thickness wavelength ratio (h / λ) is 2% to 9%.
[0045] (4) The surface coating layer is a sound-absorbing ma...
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Abstract
The invention discloses a 17% relative bandwidth low-loss surface acoustic filter, comprising a wafer material. Trapezoid surface acoustic transducers and a surface coated sound absorption layer are arranged on the wafer material. The trapezoid surface acoustic transducers comprise serial resonance arms and parallel resonance arms. The employed wafer material is 15-degree YX-LiNbO<3>. The electromechanical coupling coefficient (k<2>) of the wafer material is greater than 20%. The wafer material is applied to preparation of a broadband low-loss device. A design structure is a trapezoid design structure. The response of the filter is obtained by taking surface acoustic resonators as basic impedance elements of a trapezoid topology structure. The resonance frequency of serial resonance arm resonators and the anti-resonance frequency of the parallel resonance arm resonators form passband of the filter. The anti-resonance frequency of the serial resonance arm resonators and the resonance frequency of the parallel resonance arm resonators form out of band of the filter. The 3dB 17% relative bandwidth low-loss surface acoustic filter is realized. The simulation frequency response is shown in the figure 5. The 3dB relative bandwidth is 19%. The actually measured device center frequency is 415 M. The 3dB bandwidth is 70.6M. The relative bandwidth is 17%. The loss is 3.6dB. The inband fluctuation is 0.8dB.
Description
technical field [0001] The invention relates to a design and preparation technology of an SAW filter, in particular to a 17% relative bandwidth low-loss SAW filter and a preparation method thereof. Background technique [0002] With the increasing demand for informatization, communication has developed from the original voice and image transmission to video transmission, etc., and its data transmission bandwidth has changed from kHz to MHz or even tens of MHz. Future communication will also develop towards high speed, large capacity and high sensitivity. [0003] At present, SAW filters mainly use three substrate materials of 128°-LiNbO3, YZ-LiNbO3 and 41°-LiNbO3 to realize broadband. Among them, 128°-LiNbO3 and YZ-LiNbO3 materials can achieve a maximum relative bandwidth of about 60% of 3dB, but they need to be matched and used, and the loss is large (16-20dB). The width is different. For medium and high frequency devices, the finger width is small and the process is more...
Claims
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Login to View More IPC IPC(8): H03H3/02H03H9/02H03H9/64
CPCH03H3/02H03H9/02818H03H9/6413H03H2003/026
Inventor 闫坤坤魏勇平杨思川黄歆张恩宇
Owner 北京中科飞鸿科技股份有限公司