Design of Polarization-Reconfigurable Beam-Scanning Monopulse Phased Array

In this communication, a multifunctional phased array with polarization reconfiguration, beam scanning, and monopulse functions is presented for advanced satellite applications based on a 2 bit phase-shifting network and planar monopulse comparator. The diodes embedded in the upper patch independently control the polarization modes of the proposed phased array, including linear polarization (LP), left-handed circular polarization (LHCP), and right-handed circular polarization (RHCP). The planar monopulse comparator located in the middle layer can flexibly switch the sum and difference patterns in both azimuth and elevation planes. The bottom phase-shifting network consists of 8 x2 2 bit phase shifters, which makes the proposed phased array have beam-scanning characteristics in the azimuth plane. Therefore, both the sum and difference beams can be scanned from -50 degrees to +50 degrees in xoz plane at all polarizations. A prototype is fabricated for demonstration. When the scanning angle is changed from 0 degrees to -50 degrees in xoz plane, the measured peak gain of sum beam ranges from 11.8 to 9.1 dBi (12 to 9.5 dBic) at LP (LHCP) radiation mode. And the measured maximum null-depths of difference beam are all below -19.8 dB (-17.6 dB) with high amplitude balance in LP (LHCP) radiation mode at boresight in yoz plane. Simulated and measured results are in good agreement.