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 mu m 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 x 0.85 mm(2) 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 1.5V supply voltage. Nearly identical RF performances are achieved in the forward and the backward operations due to the symmetric circuit topology and layout.