Design and Modeling of Directional Ultra Wideband Antennas

Abstract

Recently, extensive research efforts have been devoted by researchers to the design of newlineUltra-Wide Band (UWB) antennas for a high speed data communication and newlinedesigning of UWB antennas plays a very crucial role in modern communication newlinesystems. A suitable UWB antenna should be capable of operating over an ultra-wide newlinebandwidth as allocated by the Federal Communications Commission (FCC). Due to newlinethe system features, antenna design for UWB has a variety of challenging issues such newlineas broad impedance bandwidth, gain, directivity, and radiation patterns as well as newlinecompact physical size. Good time domain performance is one of the major newlinerequirements of UWB antenna. newlineThis thesis focuses on directional UWB antennas design and modeling analysis for newlinemodern communication systems. Extensive investigations are carried out on three newlinedifferent compact structures of the antenna. These include elliptical slotted circular newlineantenna, square slotted ground plane circular ring antenna, and semi-elliptical slotted newlineground plane circular antenna. newlineThe development processes of designed antennas are investigated in detail to have an newlineapproaching into their directional ultra-wideband performance. Thus, proposed newlineantennas are designed using the concept of Defected Ground Structure (DGS) is newlinecapable of supporting multiple resonances and combining these multiple resonances newlineas result in ultra-wideband nature. Theoretical validation of the designed antennas is newlinecarried out along with equivalent circuit models to discuss UWB phenomenon. The newlinedesign aspects based on geometrical parameters of the antennas are investigated. newlineThen, simulation and measurement studies in terms of return loss, impedance newlinebandwidth, gain, directivity, radiation pattern, and time domain performance of the newlineantennas are carried out at different resonances frequencies. Simulation of the newlineantennas is carried out on Electromagnetic (EM) simulator by Computer Simulation newlineTechnology (CST) and it is designed on FR-4 substrate with dielectric constant 4.3 of thickness 1.6 mm.