Polar phase-conjugating active arrays for spectrally-efficient linear wireless links

In this paper, polar transmitter concepts for high-efficiency linear power amplifiers are applied to phase conjugating arrays, with the goal of improving spectral efficiency and linearity in full-duplex communications. The nearly linear control of the drain biasing voltage over the conversion characteristic of an active gate mixer is used to overcome the highly nonlinear AM-to-AM conversion characteristic between the local oscillator (LO) and the response signal ports. A 4-element linear patch array at 980 MHz is implemented and characterized as a polar phase conjugator for CDMA-modulated signals.