Multi-band SAW front-end module considering impedance matching between FEM and direct-conversion RF-IC

Assuming a direct-conversion demodulation method, a triple-band SAW front-end module was investigated. Based on the blocking requirements given by GSM regulation, we proposed a new FEM structure, which included three Rx-SAW filters. Low-loss and sharp-cutoff frequency characteristics was designed, especially for PR SAW filter. Differential Rx-output ports with small amplitude- and phase-imbalances were achieved by developing lumped-element baluns within the FEM. A new evaluation procedure were discussed taking into consideration not only differential-mode impedance matching at the-pass band but also impedance miss-matching at the out-of band between the FEM and a RF-IC. Experimental results are also presented.