Compact and Broadband Millimeter-Wave Mixer Based on the New Phase Relationship

A millimeter-wave monolithic mixer with new phase relationship is demonstrated and fabricated through a 0.25 mum PHEMT process. This mixer is composed of two 90deg hybrids with new phase relationships, which provides the function like the 180deg hybrids in the double balanced mixer structure. And it does not only provide flexible layout design, but also offer wideband performance. The measured results demonstrate a conversion loss of 10.2~14.5 dB over 18-40 GHz operation bandwidth, and the 1-dB compression power of 6 dBm at 27 GHz. Moreover, the LO-IF and RF-IF isolation are better than 20 dB from 28-40 GHz, and this proposed configuration leads to a die size of less than 0.48 times 0.77 mm
²
.