Wideband Circularly Polarized 2 × 2 Antenna Array With Multibeam Steerable Capability

• Published in: IEEE antennas and wireless propagation letters Vol. 16; pp. 345 - 348
• Main Authors: Tran, Huy Hung, Park, Ikmo
• Format: Journal Article
• Language: English
• Published: IEEE 2017
• Subjects: Antenna array; Antenna arrays; Antenna measurements; beam steering; circular polarization (CP); Dipole antennas; Gain; parasitic elements; Ports (Computers); triangular-shaped dipole; Wideband
• ISSN: 1536-1225; 1548-5757
• DOI: 10.1109/LAWP.2016.2576019

A circularly polarized (CP) switched-beam antenna array with the capability of generating nine steerable beams in the hemispherical space is presented in this letter. A single radiator is first constructed with two triangular-shaped dipoles crossing through printed rings, and four parasitic elements are introduced to enhance the CP operation bandwidth. For the beam steering operation, its array antennas are implemented in a 2 × 2 arrangement and fed by a four-input port feeding network composed of four double-box branch-line couplers. With a suitable feed excitation mechanism, the proposed antenna can generate CP axial beams in nine directions. The antenna is fabricated with an overall size of 2λ o × 2λ o × 0.2λ o (at 6 GHz), and the measured results demonstrate that the proposed design provided very wide -10-dB impedance and 3-dB axial-ratio bandwidths of 48.6% and 46.2%, respectively. Additionally, stable radiation patterns with a gain of approximately 11.5 dBic and radiation efficiency of greater than 90% were observed for every beam direction.