Global analysis for a surface wave mode HFET amplifier module at 60 GHz by EM-device co-simulation

A global analysis for a millimeter-wave amplifier module with surface wave mode transmission lines has been demonstrated. The analysis method is a co-simulation between an FDTD-based electromagnetic simulator and a semiconduc- tor device simulator. Using this method, it is possible to consider various electromagnetic coupling between transmission lines and active devices with nonlinear characteristics. Furthermore, a semiconductor device simulation is more accurate than an approximation to a large-signal equivalent circuit. The incor- porated simulation was demonstrated for a millimeter-wave amplifier module which consists of an HFET and planar dielec- tric transmission lines (PDTL) at 60-GHz region. The PDTL with a surface wave transmission mode has a low-loss transmission characteristic at millimeter-wave region using a low-loss ceramic substrate. However, the transmission wave on the PDTL tends to be scattered by discontinuity structures and impedance mis- matching. Furthermore, it is predicted that reflected scattered waves at edges of the substrate interfere the PDTL and transis- tors mounted on the PDTL. Using the co-simulation technique, influence of the scattering waves was investigated in detail for the amplifier module.