On-wafer HEMT characterization to 110 GHz

The accuracy of W-band on-wafer S-parameter measurements and direct equivalent-circuit parameter extraction (ECP) techniques for characterizing InP lattice-matched and pHEMTs to 110 GHz is examined. The effects of transverse propagation delays on high-frequency equivalent circuits are discussed. Measurements show that as long as pad capacitances are carefully determined, frequency-independent cold- and hot-FET ECPs can be direct-extracted across the entire frequency band from 1 to 110 GHz, and the derived models can be used to reliably design amplifiers to 110 GHz.