Arc-shaped monopole antennas with reduced coupling for WLAN and WIMAX applications

An arc-shaped planar-monopole two antennas for WLAN and WiMAX application is proposed. The lengths of the two arcs are designed to meet the requirements for the WLAN and WiMAX standard sat 2.45GHz and 3.5GHz respectively. The separation between centers of the two feed lines is 14 mm (0.098 wavelengths at 2.45GHz).A new technique is proposed to reduce the mutual coupling between the two closely-spaced antennas by etching slots in the feed line of each antenna. The slots are in the form of two interlaced letter U. In each antenna, the slot is tuned to resonate at the operating frequency of the other antenna so that the signal coupled from the other antenna is blocked from reaching the antenna port. The antenna performance was investigated by simulation using CST Microwave Studio software. The results show that the proposed method has reduced the envelope correlation coefficient by 246 folds at the 2.45 GHz, and 11 folds at the 3.5GHz frequency bands. Measured S-parameters verified the simulated results.