Performance Evaluation of Various Feeding Techniques for Microstrip Patch Antenna

Abstract

The field of mobile and wireless communication is growing at very fast rate covering many technical areas. Wireless local area network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX) technology is most rapidly growing area in the modern wireless communication. This gives users the mobility to move around within a broad coverage area and still be connected to the network. This provides greatly increased freedom and flexibility. For the home user, wireless has become popular due to ease of installation, and location freedom. So, there is continuously increasing requirements of efficient and high performance antenna .The features of antenna which every technology requires is light weight, small in size and low cost etc. Apart from this feature antenna also should have wide bandwidth and should have multiple resonant frequencies. Almost all these requirements can be fulfilled by Microstrip patch antenna. In this thesis report, the main objective is to find the best feeding technique for WLAN/WIMAX applications. A simple rectangular microstrip patch antenna is designed for a single frequency of 5.2GHz with each feeding technique. A comparison is made between all feeding techniques in terms of patch size, gain, bandwidth, directivity and radiation efficiency etc. Then, the bandwidth of a coaxial fed microstrip patch antenna is enhanced by using direct coupled parasitic patches. Next, various Microstrip antennas for different WLAN/WIMAX application with different feeding techniques are presented. The various parameters like return loss, smith chart, radiation pattern and VSWR etc have been studied and plotted for each simulated antenna. The affects of various parameters like length of the patch, width of the patch, dielectric constant in case of proximity coupling and slot location in case of aperture coupling has been presented. Finally, a fabrication procedure has been studied and two out of the simulated antennas are fabricated.