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.

This work presents a four-element multiple-input multiple-output (MIMO) antenna for super high frequency band (SHFB) applications using polarization diversity and cross-neutralization line (CNL). This structure consists of an M-shaped patches with a partial ground plan, powered by a coplanar waveguide (CPW) line. The compact system is based on polarization diversity. This configuration shifts the phase of the four antennas by 90° to provide better isolation between the different antenna ports. The cross-neutralization line blocks the current flowing between the antenna elements and thus reduces mutual coupling. The suggested structure was developed with dimensions of 31 × 31 × 1.6 mm³. It can achieve a reflection coefficient of less than −10 dB (S₁₁ < −10 dB) with a total bandwidth of 5.71 GHz (2.82 to 8.53 GHz) and an isolation of more than −10.8 dB over the desired band. Envelope correlation coefficient (ECC) less than 0.25 and diversity gain (DG) bigger than 9.8 dB are obtained and the antenna’s radiation and diversity performance are evaluated. An equivalent circuit model is proposed to represent the behavior of the single element antenna. A prototype was fabricated and experimentally tested to confirm the proposed design. In general, simulated, measured, and theoretical results are remarkably matching.