Design and performance evaluation of various Microstrip Antennas

Abstract

newline Communication systems are generally classified as narrow band and wideband systems. Wideband communication systems are further categorized as broadband and ultra-wideband (UWB). Rapid growth in UWB technology is attributed to release of unlienced frequency band 3.1 to 10.6 GHz by the Federal Communication Commissions (FCC). Wireless communication systems comprises many subsystems, the antennas is the most essential and integral part at both transmitter and reciever end. newlineWith the developments in mobile and wireless communications systems, need for compact size and wide impedance bandwidth antennas has been felt and planar antennas established their suitability due to various inherent advantages. This has been motivated us to explore the field of planar antennas and propose new structures suitable for varios wireless and mobile applications. The work in this thesis focuses on design, simulation and experimental analysis of various new or modified structures for broadband and wideband (i.e., UWB) planar antennas with and without notched stop bands. newlineIn this work, we have proposed two broadband antennas structures based on circular geometry - CPW-fed parasitically-loaded circular monopole antenna and microstrip line-fed printed circular patch antenna with two parasitic stubs. The impedance bandwidth of the proposed antennas is enhance through the bandwidth enhancement techniques such as the straight slits in the radiating patch geometry and parasitic stubs in the ground plane. It has been demonstrated that these antennas are suitable for broadband applications and provide good characterisc behaviour. newlineThe work is extended to design antenna structures for UWB application. The thesis presents modified form of rectangular and circular planar antennas, which are fed by microstrip line. Impedance bandwidth is enhanced using coupled resonators such as slots, beveling edges, slits etc. on the patch surface or on the ground plane.