Broadband resonant filter using surface-shear-wave mode and twin-turn reflector

A broadband resonant filter of a fractional bandwidth of up to 6% with an insertion loss under 3 dB has recently been developed using a surface shear wave mode on an LiNbO3 Y-X substrate. The filter is realised on a substrate with thin metal electrodes, comprising a twin-turn reflector (two 3 dB multistrip couplers and four reflectors) and two interdigital transducers, without using additional matching inductors.