A flip-chip MMIC design with coplanar waveguide transmission line in the W-band

This paper describes a design method for flip-chip monolithic millimeter-wave integrated circuits (MMIC's) with a coplanar waveguide (CPW) transmission line for W-band applications. We proposed a test structure for obtaining accurate dip-chip CPW line models. We examined the transmission line characteristics of the CPW line using the test structure in the millimeter-wave range and modeled them. Using the CPW line models, we designed and fabricated both two- and three-stage amplifiers using 0.15-mu m InGaP/InGaAs high electron-mobility transistor technology. The maximum power gain of the two-stage amplifier is 12 dB at 79 GHz, The three-stage amplifier has a maximum power gain of 16 dB at 77 GHz, The agreement of measured S-parameters with calculated results demonstrates that the proposed test structure is suitable for characterizing flip-chip CPW lines and provides very accurate models.