SAW FEMs for GSM-based multi-band cellular phones with direct-conversion demodulation

Assuming DC demodulation, the required characteristics and new configurations for SAW front-end modules (FEMs) were investigated. Parallel connections between SAW filters and the pin diode reduce the number of circuit elements drastically. The developed module for EGSM/DCS dual-band achieved Tx insertion losses as small as 1.0 dB and 1.2 dB, and Rx insertion losses of 3.0 dB and 3.3 dB for EGSM and DCS, respectively. 30-40 dB attenuation particularly required for DC demodulation up to several GHz was achieved. Multi-band FEMs such as triple-band FEMs and so on were also investigated.