A Novel C-Band Single Diode Mixer with Ultra High LO/RF and LO/IF Isolation

Abstract

A novel single diode mixer with ultra high LO/RF, LO/IF isolation and having a reasonably good conversion loss has been designed. RF and LO signals are applied through bandpass and lowpass filters respectively. The mixer operates in C-Band and downconverts a Hock of frequencies (5.925 GHz -6.425 GHz) to a block of frequencies (3.7 GHz - 4.2 GHz) using a fixed frequency local oscillator at 2.225 GHz. The proposed mixer structure achieves double balanced functionality with a single diode and obviates the need for RF and LO baluns. The measured conversion loss ranges from 8 -10 dB and port isolations are in excess of 60 dB.