Multiple‐input‐multiple‐output antenna with pattern reconfiguration and correlation reduction for WLAN applications

A Yagi‐Uda inspired novel pattern reconfigurable multiple‐input‐multiple‐output (MIMO) antenna array is proposed in this article. The antenna consists of two co‐axially excited microstrip patch radiators with modified ground plane. A conducting strip with an integrated PIN diode is optimally placed midway between two MIMO patch radiators placed at a distance of 0.22λ0 (λ0 is the free space wavelength at 2.4 GHz) apart. By switching the diode OFF or ON, the conducting strip directs or reflects the main beam of the two MIMO elements at an angle of ±30° or ±60°, respectively, thereby, enabling 30° wide band scanning and four switchable beams radiated by the two antennas. The novel MIMO antenna exhibits 17 dB isolation improvement between the two radiators when the diode is switched ON as a result of the beam deflection. For all switching modes, the MIMO antenna demonstrates an average gain and efficiency of 5 dB and 92%, respectively, at the resonance frequency of 2.4 GHz. The novel antenna is fabricated and measured to verify the simulation results. This simple, low‐cost, efficient, and mutually isolated antenna array can be very useful in MIMO WLAN applications. A beam steerable 2.4 GHz MIMO antenna array is proposed based on the Yagi‐Uda principle. The antenna consists of two co‐axially excited patch radiators with modified ground plane. A conducting strip with an integrated PIN diode is optimally placed between the patch radiators to act as a director or a reflector to steer the main beam by an angle of ±60°.