A W-Band Marchand Balun in 0.1 μm GaAs pHEMT Process

The increasing interest in fully differential W-band circuit designs poses the requirement for high-performing balun circuits. This paper proposes a Marchand balun implemented in WIN Semiconductor's 0.1 mu m GaAs pHEMT process. The circuit demonstrates excellent broadband performance across the frequency range from 82.5 GHz to 123 GHz with a measured insertion loss of 1.5 dB. The average measured magnitude and phase imbalances are less than 0.25 dB and 1.25 degrees respectively. To the best of the authors' knowledge, this is the best-reported W-band Marchand balun with minimum insertion loss and phase and magnitude imbalances.