SAW filters with very high shape factor

Abstract

Transversal filters with very high shape factor have been developed based on multiharmonic and withdrawal weighted transducers with isolated sections. The developed simulation technique provides excellent results both for in-line filter structures and those with multistrip couplers. The experimental results are presented for IF filters manufactured on YZ-LiNbO/sub 3/ and ST-quartz substrates. In-line filters exhibit SF in the range 1.15-1.2 and for MSC filters, SF values 1.05-1.1 have been obtained. For all filters the stopband rejection is more than 50 dB.