A Double-Balanced I/Q Mixer with a Fully Differential Transformer-Based Quadrature Generation Network in CMOS Technology

In this paper, a double-balanced I/Q mixer with a fully differential vertical-stacked hybrid quadrature generation network based on a high coupling on-chip transformer is demonstrated using 65 nm CMOS technology. The mixer incorporates the proposed differential vertical-stacked hybrid quadrature generation network (DVHQG) to enable good quadrature accuracy and achieve significant size reduction. The I/Q mixer exhibits a voltage gain of 6 dB while dissipating 23 mW from a 1-V supply. The magnitude imbalance and phase quadrature mismatch between I and Q channels are 0.22 dB and 0.3° from 7.7 GHz to 8.35 GHz, respectively. The achieved LO-to-RF isolation is below −72 dB. The chip dimension measures 770 × 720 μm
²
where the hybrid quadrature generation network only occupies an area of 234 × 178 μm
²
.