Recently, with the faster pace of development on the sophisticated detection and stealth technology, an extensive attention is being paid to the reduction of Radar Cross Section (RCS) as it emerge in security and commercial application. Communication based applications have greater influence depends upon design architecture and performance of an antenna. This paper proposed FSS to triumph over varying values as considering design parameters. Here, Frequency Selective Surface (FSS) is optimized with a technique said to be Particle Swarm Optimization (PSO), used for tightly coupled array (PSO-UTC-FSS). This paper intends to design an Optimized Vivaldi antenna to enhance the gain performance. More particularly, optimization algorithms play a vital role in fine-tuning of parameter, and hence this paper intends to propose a new Improved Grey Wolf Optimization Algorithm with Fitness based Update evaluation (IGWO-FU), which is the enhanced version of traditional GWO. Using above concepts, losses are minimized and hence it improves radiation efficiency, gain measurement, bandwidth ratio etc. Finally, the performance of proposed IGWO-FU model is compared over other traditional algorithms with respect to gain, VSWR, directivity, charge and current distribution, return loss as well.