Wideband homodyne six-port receiver with high LO-RF isolation

A simple wideband six-port direct receiver architecture exhibiting high isolation between LO and RF ports is presented. The proposed circuit comprises high input impedance power detectors and lumped-element artificial transmission lines. Therefore small size is achieved even at low frequencies, allowing for easy integration in MMIC technology. A proof-of-concept prototype operating in the 0.8-2.4 GHz band has been constructed and measured showing the validness of this approach.