A D-band phase compensated variable gain amplifier

This paper presents a variable gain amplifier (VGA) for D-band (110 - 170GHz) applications using metamorphic high electron mobility transistors (mHEMT) with gate lengths of 100 nm. The VGA is based on a cascode architecture with gatewidths of 2x30 J.Im and is designed with phase compensation techniques. The overall chip-size is 0.7SxO.7S mm2BL With son terminations and a 2 V supply-voltage the maximum gain is approximately 10 dB with a control range of over 16 dB. Phase deviations versus gain are less than 4° at frequencies around 161 GHz with input- and output return loss both better than -7 dB.