“…It is necessary to improve the high-frequency small-signal equivalent-circuit model for these applications. Up to now, many incremental works have been reported such as extrinsic parameter equivalent-circuit topology improvements, [15][16][17] high-frequency measurement and de-embedding methods, [18][19][20] parameter extraction method improvements of millimeter-wave transistors, [15][16][17][21][22][23][24][25] substrate and parasitic transistor parasitics extraction (for SiGe devices), 22 improvements of special biases (cold, cutoff, open-collector, and overdriven I b biases) parasitics extraction methods, and consideration of de-embedding residual parameters. 15,23 Furthermore, compared with planar HBTs, THz InP-based triple-mesa HBTs/DHBTs are different in material, device construction, and size.…”