Surface acoustic wave convolver using multiple waveguide

Abstract

AbstractA new elastic convolver is proposed in which a nonlinear interaction of surface acoustic waves (SAW) on multiple waveguides is used. Theoretical and experimental investigations are carried out. When two SAWs with angular frequency of ω and wavenumber of β, and with ω and‐β propagate in opposite directions on N waveguides, the parametric mixing phenomenon generates a SAW with a sum frequency traveling in the direction normal to the waveguide. The generation efficiency increases: (i) when the width of one of the waveguides is one‐half the wavelength of the sum frequency SAW; (ii) with the number N of the waveguides with the maximum occurring at N = 8 ∼ 10; and (iii) with the larger velocity difference (ΔV/V). Generation of the sum frequency SAW is possible only with the guided mode of SAW. The present convolver can be matched easily with the external circuit, because the convolution output is extracted with an interdigital electrode (IDT).