A 60-GHz 4th subharmonic phase-conjugated retrodirective array

A 60-GHz 4" suhharmonic phaseconjugated retrodirective Linear array with four elements is proposed. A 4th suhhrmonic phase conjugation mixer in the array is built by the combination of two anti-parallel diode pairs (APDPs) and an LPF. As compared to the previous phase conjugation mixer, the phase conjugation mixer scheme requires the 4\´h suhharmonic of the RF frequency for the LO rather than twice the RF frequency. Receive and transmit RF frequencies of 61.33 GHz and 61.53 GHz are chosen. In order to obtain an IF frequency of 100 MHz, a 4" suhharmonic of 15.3575 GHz is selected. To demonstrate the retrodirective implementation, monostatic and bistatic radar cross sections (RCSs) are measured.