Integrated antenna array with artificial magnetic conductor for IEEE802.11A application

Abstract

Microstrip antenna is a preferable choice for antenna due to low profile, low weight, ease of fabrication, inexpensive to manufacture, and adaptable to design at non planar and planar surfaces. However, the drawbacks of designing antenna using microstrip technology are low gain, narrow bandwidth, low efficiency and low power. Many research works were carried out to improve the performance of microstrip antenna. One of the techniques that increasingly attractive nowadays is the integration of metamaterial to microstrip antenna. Metamaterial is a material that not existed in nature and designed artificially. But, due to some useful characteristics of the material, metamaterial is designed as to mimic the non-naturally occurring material to improve performance of devices such as microstrip antenna. Metamaterial that is used in this research is Artificial Magnetic Conductor (AMC). AMC is designed to mimic the unique behaviour of Perfect Magnetic Conductor (PMC). PMC provides phase reflection properties in a limited frequency band. AMC acts as a modified ground plane and in-phase superstrate when positioned at the bottom substrate and top substrate of the antenna respectively. A technique of Defected Ground Structure is implemented in the AMC unit cell, enhancing its bandwidth up to 94%. An array of antenna is developed as the reference antenna at 5.8 GHz operating frequency. The array antenna is integrated with AMC ground plane and in-phase superstrate. An analysis was carried out on the performance improvement to array antenna made by the two distinguishable structures. The developed array antenna with AMC ground plane achieves bandwidth enhancement of 287% while improves efficiency up to 12%. On the other hand, the developed array antenna with in-phase superstrate successfully improves the bandwidth and efficiency of the antenna by 44% and 6%. Additionally, the integration of in-phase superstrate improves the directivity of the array antenna. It is discovered that the existence of air gap limits the gain of the array antenna with AMC ground plane. Furthermore, the air gap improves the gain of the array antenna with in-phase superstrate