Low voltage X-band InGaP/GaAs power heterojunction bipolar transistor

We report on the X-band power performance of InGaP/GaAs heterojunction bipolar transistor. At a low collector bias voltage of 5 V, a CW output power of 0.445 W is obtained from a InGaP/GaAs HBT consisting of twelve 2/spl times/15 /spl mu/m/sup 2/ emitter fingers, corresponding to a power density of 1.24 mWspl mu/m/sup 2/. The associated power gain is 7.5 dB and the linear gain and power-added efficiency are 9.2 dB and 42.6%, respectively. The device delivered 0.5 W CW output power, i.e. 1.39 mWspl mu/m/sup 2/, with 40% PAE and 6 dB power gain when the V/sub CE/ was increased to 6 V.<
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