A 17.1-17.3-GHz image-reject downconverter with phase-tunable LO using 3× subharmonic injection locking

A 17-GHz RF receiver, consisting of a low-noise amplifier (LNA) and doubly balanced mixers coupled by a monolithic 3.7:1 step-down transformer, realizes over 75 dB of image rejection in a production 100-GHz f_T SiGe BiCMOS technology. A new coupling transformer winding improves the magnetic coupling coefficient by more than 20% compared to conventional designs, which reduces parasitic effects and increases the overall efficiency of the LNA/mixer combination. Quadrature LO signals with electronically tunable phase are generated by a subharmonically injection-locked oscillator. The measured receiver IIP3 is -5.1 dBm with 17.3-dB conversion gain and 6.5-dB noise figure (SSB 50 Ω) at 17.2 GHz. The 1.9×1.0 mm² IC consumes 62.5 mW from a 2.2-V supply.