THE VOLTAGE-DEPENDENT IP3 PERFORMANCE OF A 35-GHZ INALAS INGAAS-INP HBT AMPLIFIER/

Here we report on the first IP3 results of a 35-GHz Ka-band amplifier based on InAlAs/InGaAs-InP heterojunction bipolar transistors (HBT's), The amplifier combines four 1 x 10 mu m(2) Quad-emitter HBT devices f or a total emitter area of 160 mu m(2) to achieve a gain of 5 dB and a n IP3 of 26,5 dBm at 35 GHz, IP3 was characterized over collector bias voltage and indicates that there is an optimum V-ce corresponding to a maximum IP3 to de power ratio, which is related to the HBT nonlinear voltage-dependent collector-base capacitance, A maximum IP3-to-dc pow er linearity figure of merit (LFOM) of 4.1 is achieved at a total coll ector current of 48 mA and a low V-ce of 2.25 V, This LFOM is comparab le to HEMT's at these frequencies and is expected to improve with the maturity of InAlAs/InGaAs-InP HBT technology.