A Ka-Band Folded Transformer Based Quadrature Generation Scheme

This paper introduces a folded transformer based quadrature generation scheme. The quadrature generation network is implemented with multi-turn transformer configuration and compensating capacitors. The differential input signal is converted into differential quadrature outputs with low magnitude and phase error in one transformer footprint. A 30-40GHz quadrature generation design is realized in a standard 65 nm CMOS process with 107um in diameter. This scheme achieves 0.8 dB insert loss at 35 GHz. For maximum ±0.7dB magnitude mismatch and 2° phase error, the achieved bandwidth is 28.6% (30 GHz to 40GHz). Within the operation bandwidth, the input matching is below -13 dB.