A phase shift keying modulator integrated single‐feed circular polarization agile array antenna

Abstract

This paper proposes a novel design of a circular polarization agile array antenna using two phase shift keying (PSK) modulators. The proposed antenna includes four dual linear polarization microstrip patch antenna elements, two PSK modulators, two quarter‐wavelength slot transmission lines, microstrip‐slot line transitions, and a single feed network. The PSK modulator generates phase switching of either 180° or 0° of the vertical signals of each antenna element with the aid of the four diodes. The quarter‐wavelength slot transmission lines are added to adjust the 90° phase difference between orthogonal signals of the array antenna. By controlling the PSK modulators, the proposed antenna can achieve dual circular polarization switching capabilities. A prototype antenna is used to demonstrate the antenna concept. The measured results confirm the concept with a good agreement between the simulated and measured performances. The proposed antenna has no complex circuits for RF and DC signals, and it provides a compact structure.