Equivalent circuit model for positive/negative reflection—type SAW reflectors

Abstract

AbstractAn analysis method is proposed herein which uses an equivalent circuit model as a means to evaluate positive/negative reflection‐type (PNR) SAW reflectors. The PNR reflector consists of reflecting elements which have 180° phase difference (positive and negative reflection coefficients). Each element is spaced with a period of one‐quarter wavelength. Compared with the conventional reflectors, these new reflectors have larger reflection‐efficiencies. In this paper, an equivalent circuit model for the PNR reflectors is presented. Circuit parameters can be determined theoretically by applying the finite‐element method to an infinite array. Examples are computed for two kinds of PNR reflectors on 128° Y‐X LiNbO3 or ST‐X quartz substrate. For each of them, we determined the circuit parameters and analyzed the reflection characteristics. We obtained good agreement between theoretical and experimental results.