A (35 – 45) GHz low power direct-conversion Gilbert-cell mixer in 0.13µm GaAs pHEMT technology

This paper presents the design and performance of a (35 - 45)GHz low power Gilbert-cell mixer realized in 0.13μm GaAs pHEMT technology dedicated to direct-conversion receivers. This mixer achieves moderate conversion gain (Gc = 4 ± 2dB) and high LO/RF isolation (I_LO/RF >25dB) thanks to its double-balanced architecture. As for linearity, the circuit shows average performance with measured input 3^rd order interception point (IIP3 = 3dBm) and input 1dB compression point (Pin@1dB = - 8dBm) at 42GHz. This mixer is mainly characterized both by low DC power consumption (P_DC=57mW) and low LO power drive (P_LO =-3dBm). Indeed, DC and LO levels required by other millimetre-wave Gilbert-cell mixers are generally much higher. This 2mm×1.5mm chip, that was fabricated using the D01PH (0.13μm GaAs depletion mode pHEMT) process provided by the OMMIC foundry is one of the very few millimetre-wave Gilbert-cell mixers realized in GaAs pHEMT technology published so far.