Highly integrated 60GHz SSB MMIC mixer with no DC power consumption based on subharmonic LO and CPW circuits in GaAs pHEMT technology

This paper presents the results of a novel miniature single sideband (SSB) subharmonic direct upconverter GaAs MMIC with no DC power consumption and developed in uniplanar technology. The mixer uses 100MHz I and Q signals to directly modulate the second harmonic of a 30GHz carrier, producing the required 60.1GHz RF output. Two pair of antiparallel diodes reduce feed-through of the fundamental 30GHz signal to the RF output while novel coplanar waveguide centre conductor-based structures provide matching. This 2.1mm² chip also uses a reduced-size Wilkinson divider based on asymmetric coplanar stripline and a standard size CPW 90° coupler. It exhibits a conversion loss of less than 11dB and a high image rejection ratio of greater than 20dB over a wide frequency range from 52GHz to 61GHz.