OPTIMIZATION OF FREQUENCY SELECTIVE SURFACES FOR RADAR ABSORBING MATERIALS AT X-BAND

Abstract

In present study an attempt has been made using Genetic Algorithm (GA) approach to design a broadband and thin microwave absorbing structure using frequency selective surface (FSS) for radar absorbing materials in the X-band frequency range. Several studies have been carried out on absorption/detection of radar signal using stealth technology. Radar Absorbing Materials (RAM) for Frequency Selective Surface (FSS) are increasing highly in these days. Still, it is challenging to design proper FSS for proper radar absorbing material (RAM). Therefore, in this thesis a circuit based approach has been applied to optimize the FSS structure for suitable RAM so considerable absorption in a good frequency band can be achieved. For this purpose GA has been applied. A fitness function of the optimization algorithm is the reflection loss of the absorber which is to be maximized. A wideband absorption characteristic is achieved for normal incidence. The optimized Jr results were verified using HFSS simulation. The results show that the reflection loss characteristics improve with multi-layering and with the implementation of FSS. This study presents a simple and fast approach that combines the circuital approach together with the Genetic Algorithm to design a wideband absorber.