Here we report on what is believed to be the first Q-band IP3 results of an InAlAsLnGaAs-InP based HBT MMIC linear amplifier. The 3-stage amplifier uniquely combines a "'double-balanced" design topology that incorporates a "current re-use" bias scheme. The amplifier MMIC achieves 15.4 dB of gain, 28.3 dBm of IP3, and a P,,, of 16.2 dBm at 44 GHz. The corresponding outputstage IP3/P, mtio is 5.3 which is the best reported for InP-HBTs at Q-band. The MMIC is a high complexity chip which integrates 15 HBTs and 18 Lange couplers in a 6.2x3.5 mm2 iaea, and is self-biased through 5V while consuming 108 mA. The "current re-use'' enables easier system integration while the "double-balanced" design produces wideband IP3, gain and return-loss performance. This work {demonstrates the promising linearity performance of InP-HBTs and its practical biasing capability which is attractive for Q-band receiver applications such as mm-wave digital radio. IntroductionHigh IP3 amplifiers are needed in mm-wave receiver systems such as Ka-and Q-band digital radio applications. Flor frequencies below 18 GHz, GaAs HBTs [ 13 as well as spiked and pulsed -doped MESFETs [2], [3] have demonstrated record circuit Linearity Figure of Merits (LFOM=IP3/Pd,) which are an order of magnitude better than conventional MESFET amplifiers. However for the mm-wave regime, little has been published on the circuit linearity merits of these technologies. One reason is that