Design Analysis And Fabrication Of Microstrip Patch Antennas For Wlan Applications Using Aperture Coupling Feed

Abstract

As of today, Wi-Fi (also known as WLAN) has become a standard in most computers. Almost every modern mobile, and other gadgets are being implemented with Wi-Fi technology. Wi-Fi makes it possible for the user to connect to the internet or a LAN (Local Area Network) through a wireless connection (hence the name WLAN-Wireless Local Area Network). Wireless communications have been developed widely and rapidly in the modern world especially during the last two decades. The future development of the personal communication devices will aim to provide image, speech and data communications at any time, and anywhere around the world. This indicates that the future communication terminal antennas must meet the requirements of multi-band or wideband to sufficiently cover the possible operating bands. However, the difficulty of antenna design increases when the number of operating frequency bands increases. In addition, for miniaturizing the wireless communication system, the antenna must also be small enough to be placed inside the system. However, in order to transmit and receive more information large bandwidths are required, and bandwidth enhancement is currently a popular research area. Therefore the advantages of microstrip antennas made them a perfect candidate for use in the wireless local area network (WLAN) applications. Though bound by certain disadvantages, microstrip patch antennas can be tailored so they can be used in the new high-speed broadband WLAN systems. In the thesis work the analysis of aperture coupled microstrip antenna is done using transmission line model. A single band aperture coupled microstrip antenna is designed at 5.8 GHz for WLAN applications. Then a dual band aperture coupled microstrip antenna is designed at 3.692 GHz and 5.2 GHz for WLAN applications by cutting the slits in the rectangular shaped patch and its bandwidth is improved by placing the stubs with the feedline. Then a broadband aperture coupled microstrip antenna is designed at 12.5 GHz for DBS applications. Thereafter a dual band aperture coupled stacked microstrip antenna is designed at 3.455 GHz and 5.2 GHz for wireless applications and its bandwidth is improved by introducing an air gap between the ground plane and the upper layer substrate. The fabrication of the broadband aperture coupled microstrip antenna at 12.5 GHz for DBS applications is done and the fabricated antenna is tested by the VNA model no N5222A of Agilent Technologies, whose frequency range is from 10 MHz to 26.5GHz.