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Plate wave (Lamb wave) propagation in an extremely thin quartz substrate is analyzed. A cut angle is sought that exhibits an ultrastable temperature dependence of the frequency characteristics so that the frequency changes little with temperature. Highly stable temperature characteristics of the frequency indicating second- and third-order curves are obtained. Theoretical and experimental investigations of the temperature characteristics of the frequency of Lamb waves propagating in an AT-cut quartz substrate indicate excellent agreement between the two, confirming that the reliability of the results of the present analysis is high. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 89(8): 9–15, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20262

A 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).