A Wideband Subharmonic Mixer Incorporating Signal Interference Technique Based Isolation Circuit

A broadband (8.7 GHz – 11.5 GHz) performing passive sub-harmonic down-conversion mixer using signal interference technique (SIT) is demonstrated, designed and reported in this paper. The local oscillator (LO) frequency is half of the radio frequency (RF) for the 2xsub-harmonic mixer architecture; therefore, for the RF lying in the range 8.7 GHz to 11.5 GHz, required LO frequency range is 4.25 GHz to 5.65 GHz with 0.2 GHz fixed intermediate frequency (IF). With a broadband operation, designed prototype shows single sideband down-conversion loss in the range 9.6 dB – 12.6 dB. Moreover, large-signal testing infers an adequate linear trait of the proposed design, showing -3 dBm and 11.32 dBm for the 1 dB compression point and third order input intercept point, respectively.