Inverted-F/Slot Integrated Dual-Band Four-Antenna System for WLAN Access Points

A four-antenna system applicable to compact access points of wireless local area network is proposed. The antenna topology integrates an inverted-F antenna and a folded slot antenna in the same space to reduce sizes to 15.5 mm × 7.5 mm. The inverted-F antenna operates in the 5 GHz HiperLAN band and the slot functions in the 2.4 GHz ISM band. Antenna tuning can be done without difficulty because the two are of different antenna types. Four antenna assemblies are placed at corners of a 50 mm × 50 mm board to meet the multi-input multi-output operation needs. Since the element antenna exhibits moderate directivity and the four antennas are arranged in a rotational symmetry, decent isolations are achieved in both operation bands without additional decoupling measures. The antenna structure is fully planar and can be integrated within the printed circuit board, which makes it an attractive candidate for compact access point uses.