Gain Enhancement of Circularly Polarized MIMO Antenna for WLAN/ZigBee/Bluetooth Applications

A dual-band MIMO antenna with gain enhancement is intended for Bluetooth, wireless local-area network (WLAN), Worldwide Interoperability for Microwave Access (WiMAX), and ZigBee applications. Along with increased gain, the suggested MIMO antenna generates circular polarization at 2.33 GHz and 2.44 GHz. The circular polarization offers improved and uniform coverage. The proposed antenna has dual-band response at 2.33 GHz and 2.44 GHz with reference to the return loss S 11 < -10 dB and gain of 8.07 dBi, 8.27 dBi and efficiency of 86.44%, 76.30% at 2.33 GHz and 2.44 GHz respectively. It has an average gain (dBi) of 8.17 dBi. Moreover, the proposed MIMO antenna has improved gain according to the recent requirements of wireless communications. The proposed MIMO antenna consists of double split ring slots with coaxial feeding. The radiating slot consists of both circular and rectangular double split slots. Therefore, it is easy to tune the dual-band operation by adjusting the slot lengths. Moreover, the bottom ground plane reduces the back radiation.