Millimeter-Wave Small-Signal Model Using A Coplanar Waveguide De-Embedded Sub-Model for HEMT

We propose in this study an approach to highly reliable extraction method for parasitic elements of the 0.1 μm GaAs metamorphic high electron mobility transistors. This method utilizes the de-embedding scheme for the coplanar waveguide (CPW) feeding structure by considering the distributed extrinsic parasitic elements in our small-signal model. The parasitic extrinsic capacitances are determined by modeling a PI equivalent circuit including the interaction between the sub-model (the model after de-embedding) and the CPW feedings. Extractions for the parasitic elements are performed at four different gate widths ( 2×10 μm, 2×20 μm, 2×30 μm, and 2×70 μm), and our S-parameter prediction shows the best agreement with the measurements in a frequency range of 0.5-110 GHz (0.5 GHz step) among the small-signal models reported to date.