Fully differential single-sideband diode ring mixer using optimum CPS design techniques

At microwave and mm-wave frequencies, single-sideband (SSB) and image-rejection mixers are traditionally implemented with double-balanced mixers combined with single-ended couplers and power dividers. An elegant solution is presented in this paper that overcomes the need for many baluns at the interface between the individual mixers and the couplers or power dividers. The proposed SSB mixer topology is fully-differential and uses just one coplanar strip (CPS) branch-line coupler and one CPS Wilkinson combiner. In addition to its simple topology, the design presented in this paper makes use of optimum CPS design techniques to combat the deleterious effects of unwanted common-mode propagation.