A 60 GHz MMIC dual-quadrature mixer in pHEMT technology for ultra wideband IF signals and high LO to RF isolation

A 60 GHz MMIC dual-quadrature mixer (DQM) has been designed, fabricated in a commercial pHEMT MMIC process and characterized with probed measurements. A measured down conversion loss (L_C) of 8.5 ± 1 dB over the frequency range 47 to 67 GHz is obtained with an LO to RF isolation better than 20 dB and 8 dBm of LO power. Measurements verify that the IF bandwidth is truly ultra wideband with a total IF bandwidth of 11.5 GHz. Thus, with a fixed LO signal of 58 GHz, the RF band between 53 and 64.5 GHz can be down converted directly to the base band while maintaining a high LO to RF isolation. Single resistive mixers are used for the actual down conversion which results in a high IIP3 figure of 20 dBm and virtually no DC power consumption. Furthermore, the DQM exhibit very low reflection coefficients at the RF and LO ports due to the dual-quadrature topology.