Design and research of S-type delay line structures

摘要

A surface acoustic wave (SAW) delay line structure was fabricated by using the XY112°-LiTaO₃ as the substrate. We use a double channel structure to minimize the impact of temperature drift, design the delay line as S structure. The interference of body waves is restrained and the signal of three times route is reduced by changing the transmission paths of SAW. In order to obtain better side-lobe inhibition, we tried to restrain harmonics, especially the excitation of the triple harmonics, using single finger interdigital transducer (IDT) with the metallization ratio ¿ as 0.5. By testing, the influence of the temperature drift of SAW oscillator could be decreased, the influence of third-wave reflection and the interference of the BAW could be restrained immensely. This structure plays an extremely important role to improve SAW oscillator frequency stability and measurement output accuracy.