Microwave Acoustic and Bulk Device Technique Studies.
Interim rept. 1 May-31 Oct 73,
STANFORD UNIV CALIF MICROWAVE LAB
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Work on the deposition of ZnO has been very successful in determining the optimum conditions for growth on a variety of substrates using electron microscopy. The ZnO films are now suitable for device work, and are being used in two projects aimed at greatly improving the efficiency of surface acoustic wave convolvers of completely monolithic design. One uses surface acoustic waves on epitaxial GaAs, excited by means of interdigital transducers deposited on ZnO film overlays, and has produced an improvement in convolution efficiency of more than 20 dB. The second device, which is now being designed, will use a ZnO layer completely covering an oxidized epitaxial Si layer, with convolver action occurring at the ZnO-Si interface. Several significant theoretical and experimental advances were made on the L-band bulk acoustic wave parametric convolvercorrelator. Measurements have been made of the nonlinear interaction coefficient responsible for convolver action in the LiNbO3 delay line, and of the third order elastic constant responsible for saturation. A time-bandwidth product of 930 has been achieved using the convolver as a pulse compressor on symmetrical V-chirp signals. Modified author abstract
- Line, Surface and Bulk Acoustic Wave Devices