• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.12
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• pp.10-16
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• 2003

To analyze the effects of the air-bridge parasitic capacitances on the performance of coplanar waveguide pseudomorphic high electron mobility transistors (CPW PHEMTs), the gate-to-air-bridge ( $C_{ag}$ ) and the drain-to air-bridge ( $C_{ad}$ ) capacitances were taken into account plus the conventional pinched-off cold. FET circuit model. To examine the effects of the parasitic capacitances due to the air-bridges, a variety routing schemes for the air-bridge interconnection were adopted for fabricating the 0.1-${\mu}{\textrm}{m}$ $\Gamma$-gate length CPW HEMT's. According to air-bridge schemes, the $S_{21}$ gain is affected considerably. From the results of the fabricated CPW PHEMT, the $C_{ag}$ and $C_{ad}$ is one of the important factor of decreasing the gain of HEMTs.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.2
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• pp.59-64
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• 2004

In this paper, a Cold PHEMT equivalent circuit was proposed, and it is applied to extract extrinsic resistances. By using the proposed Cold PHEMT equivalent circuit, the variation of impedance with frequency and bias were mainly emphasized. Especially, the convergence of impedance with frequency and the change in impedance with bias were carefully analyzed, which may be used for fast extraction of extrinsic resistances. The proposed extraction method demonstrated improving of small signal model accuracy than conventional extraction method.