A High-Efficiency Dual-Polarized Phase-Shifted Antenna Array With Stable Tilted-Beam Angle

Abstract

In this letter, a high-efficiency, dual-polarized, phase-shifted antenna array with a stable tilted-beam angle is proposed. To eliminate the requirement for phase-shifted feeding layers, novel array elements with phase-shifted capabilities are proposed, designed by cascading different baluns and dipoles. First, Marchand baluns and direct-fed baluns are proposed as phase shifters by analyzing their equivalent circuits and transmission coefficients. Additionally, changing the shapes of antennas is also effective to adjust the phase distributions. These methods enable antennas to exhibit phase-shifted capabilities, thereby achieving integration, low cost, and high efficiency. After careful optimization, 2-bit phase distributions of 0°, −90°, −180°, and −270° are attained. The simulated results indicate that the antenna array demonstrates reflection coefficients below −10 dB within 3.35 GHz to 3.9 GHz and a total efficiency of 94.3% at 3.6 GHz. A stable beam angle of 23° is achieved, and the variations of the beam angle are less than 1° within operating frequencies. Finally, a 4 × 6 array prototype is fabricated and a reasonable agreement is obtained between the simulated and measured results.