A CMOS Sub-Harmonic Architecture for Signal Down-Conversion at Ka-Band

Quadrature Sub-Harmonic mixing to DC or low-IF can be attractive for signal processing at Ka-band. Frequency translation is performed without the need for a local oscillator at the received signal frequency. A lower frequency reference takes advantage of the higher quality of tuning elements and avoids high frequency, power-hungry dividers in the synthesizer. Moreover DC offset and second-order inter-modulation distortion, due to poor LO-RF isolation, are mitigated by the LO running at lower frequency. This paper presents the receiver IC architecture and experiments from a quadrature demodulator realized in 65nm CMOS.