A PHEMT-Based Phase Conjugator for Full-Duplex Retrodirective Arrays

Abstract

In this letter, a phase conjugator for full-duplex retrodirective arrays is presented. Properly controlling a PHEMT nonlinear behavior, the modulation of the phase conjugated retransmitted signal is assured without distorting the information contained in the amplified version of the received signal. By means of a balanced architecture, the interrogating and response components are obtained through two mutually isolated output ports, respectively connected to the demodulation unit and the orthogonal feed of the employed aperture coupled patch. Measured results demonstrate the phase conjugator performance in two operating modes: retransmission of a BPSK signal after reception of an amplitude modulated interrogation, or ASK response when the incoming excitation is angularly modulated.

Frequency down‐converter with vector control capability for receiving phased array applications

“…Two regions of maximum transconductance variation are easily appreciated, corresponding to a peak and a valley in the G 2 curve. These regions are associated with even degree type of nonlinearities over the device I / V characteristics, specifically the pinchoff‐to‐saturation, and the saturation‐to‐linear zone transitions [5], also highlighted in Figure 1. As G 2 shows opposite sign, maximum conversion gain could be expected if properly biasing the device in those zones, but with 180°‐shifted phase conversion characteristics.…”