CMOS distributed amplifiers for UWB radar

Ultra wideband radar implementations for millimeter-/microwave operation are emerging in CMOS requiring high bandwidth. A distributed amplifier (DA) topology for use as low-noise amplifier (LNA) in nanometer CMOS, is explored in this paper. Important modifications like direct termination is beneficial both in area and gain linearity. A 5-stage amplifier provides a -3dB bandwidth of 36.5GHz and a S₂₁ of 10.7dB ± 1.5dB in the passband, while consuming 24mA from a 1.2V supply and occupying an area of 0.67mm². A 3-stage amplifier provides a -3dB bandwidth of 39GHz and a S₂₁ of 8.8dB ± 2dB in the passband, while consuming 16mA from a 1.2V supply and occupying an area of 0.41mm². Reported results are surprisingly good, indicating DA architectures are giving sufficient performance for wideband applications like chirped radars even with limited supply voltage.