A wideband transformer-coupled frequency quadrupler using an asymmetrical balun in 0.25μm SiGe for backhaul communication

A transformer-coupled frequency quadrupler with 50% bandwidth is designed in a 0.25μm SiGe process. The quadrupler covers an output frequency range from 36GHz to 60 GHz with a total power consumption of 38.5mW for a supply voltage of 2.5V. To fulfil the requirement of harmonic suppression, a novel on-chip asymmetrical Marchand balun structure is adopted to compensate the phase and amplitude errors across a wide bandwidth, so that the 3^rd- and 5^th harmonic suppressions of more than 30-dB can be achieved. The transformer-coupled approach along with a common-base configuration is adopted to enlarge the bandwidth of the multiplier.