Fully-integrated CMOS bidirectional distributed amplifier as tunable active duplexer for wireless transceiver applications

The design of a fully-integrated CMOS bidirectional distributed amplifier (DA) based active duplexer with tunable broadband high isolation capability is presented. The S₂₁ differential power gain peaks at 7 dB and then rolls off to a unity gain bandwidth of 11.5 GHz. The simulated tunable isolation performance is better than -26 dB. The simulated tunable isolation S₃₁ show a 10 dB improvement. Simulation results show that the co-design of DA based active duplexer with on-chip loop antenna has 6 dB S₂₁ power gain added improvement from DC up to 5.2 GHz compared to a matched stand alone on-chip loop antenna S₂₁ power performance. The CMOS bidirectional DA based tunable active duplexer was fabricated using the 0.13 mum CMOS technology and has a total silicon chip area of 1.887times0.795 mm².