Reduced gain variation against temperature with thermistor on HPA module for W-CDMA system

A high-power amplifier (HPA) module for wide-band code division multiple access (W-CDMA) system with small gain variation against temperature is presented in this paper. Two temperature compensation techniques, which contain gain control bias circuits that correspond to temperature or thermistors were investigated. Comparison between the above techniques indicated that the technique with thermistors was more effective in reducing gain variation without affecting linearity. A fabricated two-stage HPA module for W-CDMA system with a thermistor in its input matching network provided a small gain variation within plusmn1 dB and an ACLR under -36 dBc in the temperature range from -10 to +85degC when ACLR was measured under load mismatched conditions, VSWR=1.4:1.