A polarization auto-matching retrodirective method

A polarization auto-matching retrodirective method is proposed in this paper. Using phase conjugating circuits and polarization rotators, it can receive any polarized pilot signal and generate predictable polarized beam aimed back to the rectenna. Phase conjugation with heterodyne mixing is executed twice to lower LO frequency and reduce phase error. The polarization mismatch loss and interference between power beam and pilot signal can be decreased to improve transmission efficiency.