A Switchless CMOS Bi-Directional Distributed Gain Amplifier With Multi-Octave Bandwidth

This letter proposes a wideband switchless bi-directional distributed amplifier in a commercial 0.13 μm CMOS technology, which realizes multi-octave bandwidth with high gain and low noise figure using distributed amplifier technique and cascode-amplifier pair. The measured gain is over 10 dB and measured noise figure is 3.2-6.5 dB. The input and output return losses are better than 9 dB at 3-20 GHz. The measured output P1dB and OIP3 are larger than 8 dBm and 17 dBm at 4-15 GHz. The chip size is 0.96 × 0.85 mm² including pads. The proposed switchless bi-directional amplifier has almost the same chip size compared to the conventional uni-directional distributed amplifier. The dc power consumption is around 68 mW at 1.5 V supply voltage. Nearly identical RF performances are achieved in the forward and the backward operations due to the symmetric circuit topology and layout.