SAW GROOVED GRATINGS AT OFF-RESONANCE AND ODD HARMONIC FREQUENCIES.

The SAW reflection and bulk-wave loss characteristics of a uniform shallow grooved reflector grating are determined for the case of operation at off-resonance and odd-harmonic frequencies. For frequencies around the fundamental resonance frequency the bulk-wave loss remains small at a value which is a faction of 1% of the incident SAW power, i. e. , it is the transmission loss which constitutes the principal loss mechanism at off-resonance frequencies. When the grating is operated at the odd-harmonic frequencies, the bulk-wave loss jumps up significantly, with performance variation between the various harmonics being small. The use of shallower grooves and a larger number of them is required to mitigate this increase in bulk-wave loss and improve the grating reflectivity. 3 refs.