The temperature-dependent characteristics of an interesting InGaP/InGaAs double-channel pseudomorphic high electron mobility transistor with graded triple delta-doped sheets are systematically studied and demonstrated. By using the graded triple delta-doped sheets and InGaAs double-channel structure, the studied device exhibits temperature-dependent dc and microwave characteristics well. Experimentally, for a 0.8x100 mu m(2) gate device, the high turn-on voltage of 1.06 (0.88) V, low gate leakage current of 76 (411) mu A/mm at V-GD=15 V, high maximum transconductance of 175 (151.5) mS/mm with 1.6 (1.33) V broad operating regime (>0.9 g(m,max)), low output conductance of 0.56 (0.59) mS/mm, and high voltage gain of 306 (259) are obtained at 300 (450) K, respectively. Furthermore, good device performance with low-temperature variation coefficients under the operating range from 300 to 450 K is obtained. Moreover, good agreements between the simulated analysis and experimental results are found. (C) 2008 The Electrochemical Society. [DOI: 10.1149/1.2999371] All rights reserved.