MICROWAVE AND MILLIMETER-WAVE HIGH-EFFICIENCY POWER HBT

This paper describes AlGaAs/InGaAs and AlGaAs/GaAs Heterojunction Bipo lar Transistor (HBT) technologies applicable to power amplifiers for m icrowave and millimeter-wave frequencies. The performance of the power amplifier is characterized using power added efficiency, which is the function of maximum available gain cutoff frequency (f(max)), and col lector efficiency. HBT device structure having p(+)/p regrown extrinsi c base, compositionally graded intrinsic base, and hetero guard ring c omposed of depleted AlGaAs, are shown as technologies to improve f(max ). Novel class F matching circuit including harmonic trapping, are als o shown as a technology to increase collector efficiency. RF power per formances of 25.6 dBm (365 mW) saturation power and 23% power added ef ficiency were obtained at 25.2 GHz.