Carrier recovery loop for millimeter-wave heterodyne receiver

A carrier recovery loop process, for a millimeter-wave heterodyne receiver, is proposed in this paper. The millimeter-wave frequency conversion is performed using a six-port module, avoiding the conventional millimeter-wave active costly mixers. The second frequency conversion is performed using conventional circuits. The carrier recovery is done at the intermediary frequency (IF) part and not at the millimeter-wave one. In this paper, the carrier recovery is demonstrated by showing the spectrum and corresponding waveform of the recovered signal, extracted through the loop from the IF received signal and used for the second frequency conversion. The bits received are transmitted by an arbitrarily incoming QPSK modulation.