Reducing spurious signals in LiNbO3 acoustic-wave convolvers

For surface-acoustic-wave convolvers, simple ways to reduce spurious signals caused by re-reflection and direct generation of electromagnetic and acoustic waves in interdigital transducers (IDTs) are suggested and tested in an experiment. The approach is based on the grounding of the transducer electrodes and the waveguide and using acoustic expanders that attenuate spurious echoes from the transducers.