Star mixer with high port-to-port isolation

The authors describe the realisation of a hybrid star mixer with enhanced port-to-port isolation, which uses novel double-Y baluns. The mixer has a minimum conversion loss of 5.5 dB and has >1.5 GHz IF bandwidth and 6.5 GHz LO/RF bandwidth for a conversion loss of <9 dB. LO/RF isolation is better than 30 dB and LO/IF isolation is better than 25 dB in the 5-10 GHz range.