An Overlapped Switched-Beam Antenna Array With Omnidirectional Coverage for 2.4/5.8 GHz Three-Channel MIMO WLAN Applications

In the design of smart antenna, switched-beam technology is widely used to increase the communication capacity and to reduce electromagnetic interference. This letter presents a switched-beam antenna array for the three-channel multiple-input–multiple-output (MIMO) wireless local area network operating in 2.4/5.8 GHz. In the proposed array, there are 12 directional beams, and every four partially overlapped beams form a channel. Thus, the proposed array provides three channels. For each channel, the four antenna elements used to radiate directional beams are rotationally symmetrical. Therefore, for all channels, good omnidirectional coverage is obtained by dynamically switching directional beams. To demonstrate the effectiveness and advantages of the proposed array, a prototype is fabricated and measured. In it, the peak gain of directional radiation reaches 9.5 dB, and the values of the horizontal plane fluctuation for three channels are smaller than 5 dB.