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

A novel method for achieving a high-efficiency, dual-polarized, tilted-beam antenna array with a stable beam angle is proposed in this article. To eliminate the requirement for phase-shifted feeding layers, four novel array elements possessing phase-shifted capabilities are introduced. These elements are designed by combining two different baluns and two different dipoles with relative phase distributions of 0°, -90°, -180°, and -270°. To achieve the states of 0° and -90°, the equivalent circuits of the Marchand balun and the direct-fed balun are analyzed with similar sizes to ensure ease of assembly. Subsequently, the two types of baluns are rotated by 180° around the phase center, leading to the states of -180° and -270°. Additionally, to maintain a stable beam pointing throughout the operating frequency range, two distinct loop dipole elements are designed to adjust the group delay of these relative phases. The simulated results indicate that the antenna array demonstrates a reflection coefficient below -10 dB within 3.35 to 3.9 GHz and a total efficiency of 94.3% at 3.6 GHz. A stable beam angle of 23° is accomplished without employing phase-shifted feeding layers, and the variations of the beam angle are less than 1° within the operating frequency range. Finally, a 4  6 array prototype is fabricated and a reasonable agreement is obtained between the simulated and measured results.