Mixer linearization using dynamic bias circuit with an integrated diode linearizer

Broadband receiver design for multi-band multi-standard and software defined radio (SDR) applications has a strong demand for high linearity RF mixers with low power consumption. This paper presents a simple and compact circuit technique for mixer linearization employing a diode linearizer integrated with the mixer's bias circuit. This novel linearization technique effectively compensates the nonlinear distortion and the gain compression of the heterojunction bipolar transistor (HBT), greatly enhancing the mixer linearity at no additional DC power consumption. The proposed mixer is fabricated, together with the conventional design, in a 250 nm SiGe BiCMOS process and tested. Measured results show that with the proposed linearization IIP3 and P-1dB are improved to 18 dBm and -3 dBm from 3 dBm and -9 dBm, respectively.