A High-Gain Reconfigurable Beam-Switched Circular Array Antenna Based on Pentagonal Radiating Elements Fed by Mutual Coupling for Sub-6 GHz Wireless Application Systems

Abstract

This paper presents the design and development of a reconfigurable circular array antenna capable of producing ten distinct radiation beams, intended for wireless systems in the sub-6 GHz frequency band. The antenna structure is based on four pentagon-shaped radiating elements arranged symmetrically around a central circular patch, which is excited through a coaxial feed. These radiating elements are linked by four circular segments, ensuring mutual coupling for effective operation. A systematic dimensional analysis has been conducted to optimize electromagnetic performance, resulting in a compact and efficient architecture. The beam reconfiguration is achieved through the control of four PIN diodes, which allow the main radiation beam to switch among ten different orientations in the azimuth plane. Specifically, the antenna supports eight directional states, oriented at 45° intervals, and two additional bidirectional states covering opposite directions. A prototype has been fabricated and experimentally validated, confirming the steering capability of ±40° in both the XZ and YZ planes. Performance evaluation shows a maximum gain of 9.29 dBi and efficiency levels ranging from 91% to 97%. Bandwidth varies across states, with 9.72% for S1–S7, 7.45% for S2–S8, and 4.61% for S9–S10. Overall, the proposed design demonstrates optimized bandwidth, gain, efficiency, and complete azimuthal coverage.