论文部分内容阅读
本文简要地介绍了在YZ铌酸锂基片上制作的、中心频率f=65兆赫,3分贝带宽△f_(3db)=11兆赫,矩形系数K_(0.01)(△f_(40db)△f_(30db))=1.24,带内波动△R≤0.8分贝(最高峰与最低谷的起伏)△b≤0.3分贝(带内相邻峰间的起伏),旁辨抑制SS≥45分贝平顶损耗 IL(f_0)≤18分贝的声表面波滤波器的结构与设计方法.通带波动是由两种起伏迭加而成,即快变化的锯齿状波纹和慢变化的起伏.前者是由三次过渡信号、电磁直通信号、基片边缘反射等形成,后者是由外电路,衍射等造成的.文中采用部分转移多条耦合器与假换能器配合等抑制三次过渡回波,通过依靠近基片边缘一侧的有源、无源指电学短路,且使二短路块相差四分之一声波长进一步抑制指间相干反射.利用频谱互补技术补偿通带内的慢起伏.设计一个换能器的频响为下四的“馒头”形,补偿由于外电路,衍射等使频响为上凸“馒头”形的另一换能器,以获得满意的平顶通带.对于部分转移多条和假换能器配合抑制包括声电再生在内的三次过渡信号的可能性,假电极相干反射抑制等进行了某些理论上的计算和讨论.
This paper briefly introduces the fabrication of YZ lithium niobate substrate with a center frequency of f = 65 MHz, a 3 dB bandwidth of Δf_ (3db) = 11 MHz and a square coefficient of K_ (0.01) (Δf_ (40db) Δf_ (30db )) = 1.24, in-band fluctuation △ R≤0.8 dB (fluctuation of the highest peak and the lowest valley) △ b≤0.3 dB (undulation between adjacent peaks in the band), side-by-side suppression SS≥45 dB Flat top loss IL f_0) ≤ 18 dB SAW filter structure and design method. Passband fluctuations are superimposed by two ups and downs, namely, rapid changes in the jagged ripple and slow fluctuations. The former is composed of three transition signals, Electromagnetic through signal, the edge of the substrate reflection, which is caused by the external circuit, diffraction, etc .. In this paper, the partial transfer of multiple couplers and fake transducer with inhibition of three transitional echoes, by relying on the edge of the substrate near One side of the active and passive refers to the electrical short circuit, and the two short circuit block a quarter of the sound wavelength to further inhibit coherent reflection between the fingers. The use of spectral complementary techniques to compensate for the slow fluctuations within the passband. Design a transducer frequency Ring for the next four “bread” shape, due to compensation for external circuits, such as diffraction to make the frequency response convex “bread” Of the other transducer to obtain a satisfactory flat top passband for the partial transfer of multiple and pseudo-transducer with the suppression of the three transitional signals including acoustic and electrical reproducibility of the possibility of false electrode coherent reflection suppression carried out Some theoretical calculations and discussions.