80-100 GHz broadband amplifier MMIC utilizing CPWs and quarter micron InP-based HEMTs

A broadband monolithic amplifier utilizing coplanar waveguides on InP substrate for applications in the frequency range from 80-100 GHz (W-band) is presented. The circuit is realized with lattice matched InAlAs/InGaAs/InP HEMTs with a gate-width of W/sub G/=2/spl times/40 /spl mu/m and T-gates with a gate-length of L/sub G/=0.25 /spl mu/m. Coplanar waveguides and lumped elements are used for the matching and biasing networks. The modeling of the amplifier was based on small signal equivalent circuit descriptions using lumped elements for all discontinuities such as airbridges, T-junctions and MIM-capacitors. The circuit is fully passivated and contains common ports for the gate and the drain bias. At a frequency of 94 GHz the amplifier reaches a gain of 15.5 dB, an input matching better than -8 dB, and an output matching better than -20 dB. The 3 dB-bandwith of the amplifier is greater than 20 GHz.