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本文概括地介绍了78年研制出的f_0=70兆赫、△f_(3db)=11%f_0、K_(0.01)≤1.36、SS≥49分贝、IL_(min)≤11.5分贝、△b≤0.80分贝的声表面波滤波器样品设计方法及改进措施.用计算机计算了最佳孔径、叉指菲涅水区和衍射张角,采用与国外文献略有不同方法:在“全转移”通道上,两换能器错开距离α,以减少衍射和束转向的影响,文中并给出α的计算公式.据tancrell、Marshall的观点,这已是非全转移型多条,但本文通过对样品数据处理,初步认为在该条件下按全转移处理是可行的,且可能降低衍射、束转向影响.文中采用了把同一取样点的分裂指相连法,使真指和假指间隙相对的另一分裂指电极以铝膜相连,借以降低波前畸变和断指的影响.但这些措施的有效程度尚待今后进一步考查.文中所给出的修正量α的公式是否有普遍性,也有待于今后验证.
This paper presents an overview of the f_0 = 70 MHz, Δf_ (3db) = 11% f_0, K_ (0.01) ≤1.36, SS≥49 dB, IL_ (min) ≤11.5 dB and Δb≤0.80 dB And the improvement measures are given.With the computer, the optimal aperture, Fresnel water area and diffraction angle are calculated by the computer, and the method is slightly different from the foreign literature: on the “full transfer” channel, two Transducer stagger distance α, in order to reduce the diffraction and beam steering effect, the paper gives the formula of α.According to tancrell, Marshall point of view, this is non-full metastasis type, but this article through the sample data processing, initially that In this condition, it is feasible to perform full transfer and possibly to reduce the diffraction and beam steering effects. In this paper, the split finger method of the same sampling point is used, and the other split finger electrode which makes the real finger and the false finger gap opposite is made of aluminum Film in order to reduce the wavefront distortion and the influence of broken fingers, but the effectiveness of these measures remains to be further examined. The formula given in the correction α whether there is universality, but also to be verified in the future.