SAW RF Spectrum Analyzer/Channelizer Using a Focusing, Phased Array Transducer

Abstract

The principle of Fourier t ransformation by wave diffraction has been demonstrated using surface acoustic waves. The input RF signal d rives a phased array of SAW interdigital transducers that act like a curved diffraction grating to focus and angularly disperse the generated acoustic waves with frequency. An array of output t ransducers partitions t he dispersed signal spectrum into contiguous narrow bands. The approach is novel and has a number of significant features. The device is passive, linear, and bidirectional, and preserves phase information. S idelobes and spurious signals can be suppressed by amplitude w eighting the input transducer elements and using mode selective output transducers. Several experimental devices has been constructed on LiNb03. These were evaluated electrically and with a scanning laser probe.