12-40 GHz low harmonic distortion and phase noise performance of GaAs heterojunction bipolar transistors

GaAs-AlGaAs heterojunction bipolar transistors (HBTs) have been used to demonstrate the capability of low harmonic distortion with high efficiency and low-phase-noise performance in the 12-40-GHz frequency regime. A simplified 3- mu m emitter, self-aligned base metal HBT process is used to fabricate transistors with f/sub max/ approximately=30-50 GHz, high linearity, and low 1/f noise, yielding significantly improved third-order intermodulation product intercept point (IP3) and oscillator performance. The HBT IP3 ranges from 20-35 dBm for 12-20 GHz with a linearity figure-of-merit ratio, IP3(mW)/input DC power (mW), approximately=4 to 20 times higher than comparable HEMTs (high-electron-mobility transistors) and MESFETs at 12 to 37.7 GHz with -82 dBc/Hz phase noise at 100-kHz offset. It is concluded that these capabilities make HBTs attractive for high-IP3 amplifiers and mixers and low-phase-noise voltage-controlled oscillators in advanced receiver applications.<
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