Differentially T-shape slot antenna with high common-mode suppression for 2.4/5.2/5.8 GHz WLAN MIMO systems

A novel design of a dual-band microstrip slot antenna with high common-mode(CM) suppression for wireless local area network(WLAN) multiple-input-multiple-output (MIMO) systems is proposed in this paper. The proposed MIMO antenna element consists of a T-shape slot and a inverted U-shape microstrip feed line. The T-shape shot includes both open-ended and short-ended slots. Open-ended and short-ended slots are exploited to obtain two resonant modes, whose center frequencies can be adjusted by the slot lengths. The T-shape slot on the top layer is fed by a pair of differential microstrip lines by proximity coupling. Simulated results show that the -10 dB impedance bandwidth of the MIMO antenna covers the 2.4/5.2/5.8 bands for WLAN applications. The measured isolation is better than 15dB for differential-mode(DM) signs in all bands. Besides, the radiation performance is also measured.