Design of Broadband Antennas with Enhanced Gain Based on Meta materials

Abstract

The ancient Greek prefix, META (means quotbeyondquot or quotaway fromquot), has newlinebeen used to describe materials with some exceptional features usually not existing in newlinenature. Depending on the exhibited electromagnetic properties, various names have newlinebeen introduced in the literature such as metamaterial, double negative (DNG) newlinematerials, left-handed (LH) materials, materials with negative refractive index (NR), newlineMagneto materials, Soft and hard surfaces, High impedance surfaces, artificial newlinemagnetic conductors (AMC), etc. newlineSome microstrip antennas based on the concept of metamaterial have newlinebeen proposed in this work. Various aspects of antenna such as size, radiating newlinefrequency, bandwidth, beamwidth, gain and directivity have been taken under newlineconsideration. Some of these parameters are contradictory to each other. It means that newlineimprovement in one parameter, results in deterioration in other parameters. In such newlinesituations, picking up a right antenna is depending up on the application. Only the newlineapplication of the antenna can decides the priority order of the above said parameters. newlineIn this thesis some new structures are proposed. Simple designing, ease newlinein fabrication, return loss, side lobe magnitude, main lobe direction, gain and newlinedirectivity have been considered prominently. Eforts are made to get an optimum newlinedesign solution. All proposed antenna are radiating between 1 GHz to 6 GHz. newlineDimensions of these antennas are vary from 28 mm X 30 mm to 120 mm X 120 mm. newlineSimulations and Laboratory results indicate the improvements in Return Loss, Gain, newlineDirectivity and size reduction with respect to previously reported work. All designs newlineare simulated with CST Studio Suite 2010. newline