A High LO-to-RF Isolation E-band Mixer with 30 GHz Instantaneous IF Bandwidth in 90nm CMOS
This paper demonstrates a single-ended down-conversion mixer with a wide IF bandwidth. The proposed mixer utilizes a modified cascode design with a CS amplifier transistor and a cold-biased (Vds=0) mixing transistor. The cold-biased mixing transistor enables wide IF bandwidth, and the CS transistor boosts conversion gain without significantly reducing IP1dB. Additionally, the LO-to-RF isolation is improved by two pairs of LC resonators. When pumping by an 8-dBm LO power at 60-GHz, the mixer exhibits 30 GHz IF bandwidth. Over the full E-band, the conversion loss is between 9 and 12 dB. The measured LO-to-RF isolation is 40.8 dB, while the RF-to-IF isolation is better than 38 dB. The IP1dB ranges from -2 to 4 dBm in the full RF band.