This paper discusses performance improvement with the integration of an artificial magnetic conductor (AMC) into array antennas. An AMC with defected ground structure (DGS) was designed to construct the AMC ground plane and in-phase superstrate. The two distinguishable structures were integrated into an array antenna, which serves as a reference antenna at 5.8 GHz. The impedance bandwidth (BW) of the reference antenna significantly improved to 287% when integrated with an AMC ground plane and with 37% reduced size. On the other hand, the integration of in-phase superstrate effectively enhances the gain and BW of the reference antenna by 1 dBi and 44%, respectively. The effects of air gaps on the reference antenna with both the AMC ground plane and in-phase superstrate are discussed. The antenna performance factors, such as return loss and radiation pattern, are also discussed for the reference antenna, the reference antenna with the AMC ground plane, and the reference antenna with in-phase superstrate, respectively. There is satisfactorily good agreement between the simulation and measurement results. The proposed antenna is useful in WLAN (5.15-5.35 GHz and 5.725-5.825 GHz) and WiMAX (5.725-5.825 GHz) applications.
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