Design and realization for radar cross section reduction of patch antennas using shorted stubs metamaterial absorbers

Abstract

This thesis is devoted to analyzing of the Radar Cross Section (RCS) of rectangular patch antenna using Metamaterial Absorber (MMA) and the analysis of its reducing techniques. The addressed theme has a great complexity and it covers various areas that include designing and optimization of target geometrical model of rectangular patch antenna structures and making it compatible with respect to metamaterial geometry. Analyses have been made to optimize and validate the structure performances that include numerical methods for electromagnetic field computation, MMA behavior, characterization, extraction of parameters, antenna radiation performance analyses, simulation, fabrication, testing, and optimization with back validating the designs. The MMA structure finds its applications in antenna designing for the reduction of Monostatic and Bistatic RCS in stealth platform for lower detectable objects. However, there is still more emphasis needed to devote for in-band frequency response for low RCS of the antenna. Therefore, making these assumptions, we have been proposing novel designs of single-band, dual-band, and triple-band MMA structures. These structures provide significant scattering characteristics and offering flexibility to the designer to control and tune the resonant frequency, based on the specific applications as compared to that of the other MMAs in the microwave regime of the Electromagnetic (EM) spectrum. To explore the research scope, a three dimensional Frequency Selective Surface (FSS) structure has been analyzed and its simulation responses with respect to parametric analyses have been made. The research investigation further extended to Electronic Band Gap (EBG) Structure and Defected Ground Structure (DGS). A hybrid structure of patch antenna is proposed and designed for an inset feed rectangular microstrip patch antenna operating at 2.45 GHz in the Industrial, Scientific, and Medical (ISM) band. This hybrid structure claims the size reduction, bandwidth, and gains enhancement. The main focus of this research work is limited to determine the potential and practical feasibility of MMA’s to enhance the stealth performance of rectangular patch antennas. For this purpose, Monostatic and Bistatic RCS simulation and measurements are carried out in an anechoic chamber and practical methods for Radar Cross Section reduction are discussed and analyzed