Resonant Inc.
High isolation surface acoustic wave duplexer

Abstract:

A duplexer includes a surface acoustic wave (SAW) device comprising a transmit filter and a receive filter formed on a piezoelectric substrate. The transmit filter includes a first transmit shunt resonator connected to a first transmit-filter ground terminal. The receive filter includes a first receive shunt resonator connected to a first receive-filter ground terminal. A ground coupling capacitor is connected between the first transmit-filter ground terminal and the first receive-filter ground terminal.