Precise design technique for a SAW-resonator-coupled filter on 36/spl deg/ YX-LiTaO/sub 3/ for use in a GSM SAW duplexer module for satisfying all GSM system specifications

A miniature low-loss high-performance surface acoustic wave (SAW) duplexer module consisting of a receiver top filter (R1), transmitter final stage filter (T1), lumped matching-circuit elements and lumped phase-shift circuits has been developed, and its use in the Global System for Mobile Communication (GSM) is described as a design example. The complete duplexer module has an insertion loss of less than 1.3 dB (890 to 915 MHz) in the Tx-to-antenna path and of less than 2.9 dB (935 to 960 MHz) in the antenna-to-Rx path. The size of the duplexer module is 14/spl times/8/spl times/1.8 mm and it weighs 0.4 g. This module satisfies the various required frequency characteristics specified in GSM standard and provides sufficiently high power handling capabilities under burst-mode operation.