Transformer-Based Broadband High-Linearity HBT ${ Gm}$-Boosted Transconductance Mixers

A Gm-boosted transconductance configuration mixer is proposed. Based on this topology, two broadband monolithic InGaP HBT mixers, one single device and one balanced, have been developed for C- Ku-band applications. The single device mixer has a conversion gain of 4.5±1.5 dB within the RF frequency range from 5 to 17 GHz. The balanced design has about 3.5±1.5-dB conversion gain within a frequency range of 6-18 GHz. The two mixers have very good linearity with a third-order intermodulation intercept point (IIP3) higher than 16 and 20 dBm for the single device mixer and single balanced mixer, respectively. Both mixers are pumped by a local oscillator power of 5 dBm. To the authors' best knowledge, the designed mixers demonstrate the highest IIP3 with positive conversion gain in this frequency range. Compact designs are achieved with chip sizes less than 0.5 mm
²
. DC power consumptions are 30 and 50 mW, for the single device and single balanced mixer, respectively.