A Polarization Agile Self-Oscillating Active Integrated 2×2 Array Antenna Using PSK Modulators

A polarization agile self-oscillating active integrated 2×2 array antenna (AIAA) embedding a Gunn oscillator and four PSK modulators is presented in this paper. With the aid of the two PSK modulators among four, the phase of the signals fed to one of the polarization of the dual-polarized antenna can be altered, while the other two are used for carrier polarization wave. Thus, the proposed antenna can provide polarization modulated radio waves by switching between ±45°. The concept is experimentally validated and has an EIRP of 27.4 dBm, DC-to-RF efficiency of 10.9%, and an oscillator figure of merit (FOM) of -169.9 dBc/Hz at 9.48 GHz. The proposed concept is found to be feasible and better than 20-dB cross-polarization suppression is obtained.