Analysis of RF performances of GaN MESFETs including self-heating and trapping effects

Abstract

A physics-based large-signal model of GaN-MESFETs is reported which includes temperature dependences of transport and trapping parameters. RF power performances are analyzed using generalized Volterra series techniques. At 2 GHz, the calculated maximum output power of a 0.3 /spl mu/m/spl times/100 /spl mu/m GaN MESFET is 22.8 dBm at a power gain of 6.1 dB and power added efficiency of 28.5%. The corresponding quantities are in excellent agreement with the measured values of 23 dBm, 5.8 dB and 27.5%, respectively. At 2 GHz, gain compressions, due to self-heating effects, of 2.2 dB and 0.75 dB are obtained for 0.30 /spl mu/m/spl times/100 /spl mu/m and 0.75 /spl mu/m/spl times/100 /spl mu/m GaN MESFETs, respectively. At 4 GHz and 10 dBm output power, the calculated third-order intermodulations (IM3) for 0.30 /spl mu/m/spl times/100 /spl mu/m and 0.75 /spl mu/m/spl times/100 /spl mu/m GaN MESFETs are -56 dBc and -44 dBc, respectively. For the same devices, IM3 increases by 6 dBc and 3 dBc due to self-heating effects, respectively.