Recently, with the rapid development of detection and stealth technologies, stealth military platform designs have attracted more and more attention. Many of this technologies that have been introduced for stealth technology, suffer from design complexities and a limited operational bandwidth. Metasurfaces are two-dimensional (2D) equivalent of metamaterials; they can serve as an alternative approach to address the bandwidth and thickness issues of the former stealth technology categories. In this thesis, we want to design and simulate an ultra-wideband metasurface for radar cross section (RCS) reduction application. We use the cell that introduced in another research for designing metasurface, this cell have two metallic patches, we make different types of cells with changing size of the patches. Reflection phase of these cells was simulated with CST microwave studio. Through the use of particle swarm optimization algorithm, 16 cells were selected and then simulated y CST MWS for x- and y-polarized normal incident waves. The metasurface can realize RCS reduction in a frequency range from 4.5 to 20.4 GHz, this result is optimal i thi thesis, but bi-static RCS reduction in a frequency range from 5 GHz to 20 GHz is lower than 7.5dB and is not optimal i thi thesis. In order to find theoptimal layout of metasurface for lower bi-static RCS, many random blocks distributions were performed by MATLAB, the bi-static RCS reduction of these distributions were approximated by semi-analytical equation that was introduced in this work, frequencies from 5 to 20 GHz with an interval of 1 GHz were considered, an optimal meta-particle surface layout with minimum bi-static is chosen, then this metasurface is simulated i the CST MWS. The metasurface can reduce RCS in a frequency range from 5 GHz to 20 GHz, this result is optimal i thi thesis, but bi-static RCS reduction in a frequency band from 5 GHz to 20 GHz is lower, approximately about 10dB. It is obvious that in the case of TM polarized and TE polarized incident waves, in the incident angles 15 degree and 30 degree , the operation bandwidth of the metasurface is approximately from 5 GHz to 20 GHz, this result shows good angular stability of the proposed metasurface. Radar Cross Section , Particle Swarm Optimization , Metasurface, Angular Stability
