ANALYSIS AND DESIGN OF MICROWAVE COMPONENTS USING METAMATERIALS

Abstract

A theoretical investigation of the design of the basic unit cell structure for metamaterial has been carried out in this thesis work which shows a negative refractive index in a particular range of frequency. The basic unit cell structure for the metamaterial was studied and designed using a split-ring resonator which affected the permeability of the medium and the wire structure which affected the permittivity of the medium. This designed metamaterial structure showed a negative refractive index in the frequency range of 2.25 GHz to 2.5 GHz. With this basic knowledge of metamaterials, a complementary split ring resonator (CSRR) loaded microstrip patch antenna was designed with a resonant frequency of 4 GHz. An array of CSRR is etched at the ground plane of the antenna affected the permittivity of the medium and helped in achieving size miniaturization of a microstrip patch antenna. The CSRR loaded patch antenna showed a size reduction of 33% when compared to the size of a conventional microstrip patch antenna designed at 4 GHz. Then a double-superstrate configuration (DSC) was used to enhance the directivity and the gain of the designed CSRR loaded microstrip patch antenna at 4 GHz. The thickness of two superstrates and the air gaps were optimized which increased the directivity of the antenna by 2.51 dBi and its gain increased by 1.87 dB. Thus the CSRR loaded patch antenna with DSC helped in achieving size miniaturization as well as improving the performance parameters of the designed patch antenna. Then a CSRR loaded wideband bandpass filter with a capacitive gap in the transmission line was analyzed and designed. The designed bandpass filter has its lower cut-off frequency equal to 2.026 GHz and the upper cut-off frequency equal to 4.775 GHz. The bandwidth of the designed filter was calculated equal to 2.750 GHz and its central frequency equal to 3.375 GHz.