New band-switching SAW antenna duplexer used in 800-MHz Japanese cdmaOne systems

Japanese 800-MHz cdmaOne systems have not only reverse frequency allocations for the transmitted and received frequency bands, but also the very wide frequency bandwidth of 38 MHz for each band and the narrow frequency spacing of 17 MHz between two bands. We have developed a new band-switching SAW antenna duplexer for these systems. Each of the transmitter-line and receiver-line filter consists of a wide-band SAW bandpass filter and an SAW band-rejection filter of which rejection band can be shifted by switching circuits corresponding to low (L) and high (H) bands. The duplexer module size is as small as 10/spl times/8/spl times/2 mm3 and the required specifications for cdmaOne were satisfied.