Design of Gap Coupled Sectoral Antennas for Communication Systems

Abstract

Microstrip patch antennas are used widely in the microwave fre¬quency region because of their simplicity and compatibility with printedcircuit technology, making them easy to manufacture either as standalone elements or as elements of arrays In its simplest form a microstrip antenna consists of a metallic patch, usually rectangular shaped or circular shaped on top of a grounded substrate Microstrip antennas have applications in different communication sectors eg mobile communications, satellite communications, radar communications, and many more wireless communications newlineIn this thesis, investigations are carried out to study gap coupled sectoral patch antennas Gap coupled sectoral patch antennas are studied with the help of circuital analysis, cavity model and tested through simulations and experimental measurements Bandwidth enhancement along with good radiation characteristics have been achieved using these sectoral gap coupled patch antennas Single patch antennas have been tested and extended to array designs Array designs have resulted in the enhancement of impedance bandwidth and improved gain with reduced side lobe level to a very good extent as compared to single patch sectoral antennas Although the single sectoral patch antenna designs proposed in this work, have also a lot of applications in various wireless communication systems A circular disc patch antenna with coaxial feeding is divided into two sectors is considered and analyzed using circuital methods The circuital method is used to calculate admittance between the walls of two sectors which is the base of analysis in this design A wideband is obtained with good impedance matching for this antenna This work is extended to four sectoral antennas A novel four sectoral gap coupled antenna design with moving excited sectoral patch is analyzed using simulations and experiments All the four sectors are parasitically coupled and bandwidth enhancement has been achieved along with good antenna gain and reduced side lobe level to a good extent