Inter modulation distortions of SAW duplexer are simulated by signal flow approximation and measured for 3.0mm and 2.5mm size SAW duplexers for Bandl WCDMA terminals. A good agreement, between simulations and experimental results are observed. We also show effective circuit for inter modulation of lower band blocker from assuming obtained analysis results. These assuming is verified by experiments. These results are used for inter modulation distortion analysis of RF block for two kids of antenna front-end circuit.