Compact switched and reconfigurable 4-ports beam antenna array for MIMO applications

In this paper, we analyze and introduce a practical design for a switched beam planar antenna that can be implemented as a compact and low cost switched and/or reconfigurable beam antenna array. The antenna is composed of a four ports antenna array based on arranged eight L-shaped quarter-wavelength slot antenna elements. This type of antenna array is a planar structure and its maximum directional radiation beam pattern presents in azimuth plane with the covering of 360 degree. The operation of antenna array is based on the statuses of ON/OFF stage of PIN diodes in each individual slot antenna element and the combined signals from four ports. Consequently, by proper controlling the stage of PIN diodes, the antenna can exposes its characteristic of switchable and/or reconfigurable beam patterns in φ-plane. The antenna array size is about 56 mm in square with four ports. To prove the concept, a 2.5–2.8 GHz switched-beam antenna for WLAN applications in MIMO is simulated and fabricated.