The property of self-similarity, recursive irregularity, and space filling capability of fractal antennas makes it useful for various applications in wireless communication, including multiband miniaturized antenna designs. In this paper, an effort has been made to use the metamaterial structures in conjunction with the fractal patch antenna, which resonates at six different frequencies covering both C and X band. Two different types of square SRR are loaded on the fractal antenna for this purpose. Particle swarm optimization (PSO) is used for optimization of these metamaterial structures. The optimized metamaterial structures, after loading upon, show significant increase in performance parameters such as bandwidth, gain, and directivity. 1. Introduction The non-integral dimensions, recursive irregularity, and space filling capability of fractal antennas make it useful for various applications in wireless communication including miniaturized antenna designs [1]. Their property of being self-similar in the geometry leads to antennas of compact size with simplified circuit designs. Antennas, which have fractal geometry, are self-iterative, exhibiting multiband operation. Fractal antennas are frequency independent and have schemes for realizing low sidelobe designs. An antenna with fractal geometry is preferred to conventional antenna designs due to the iterative behavior of the structure, which is believed to improve the performance factors like gain, bandwidth, return loss and frequency of operation [2]. Metamaterials are artificial structures designed by placing electromagnetic (EM) resonators, such as split ring resonators (SRRs), at regular intervals. The metamaterials have frequency selective response and exhibit unique EM properties such as negative permittivity and permeability, artificial magnetism and negative refractive index, which can be used to improve the performance of antenna [3]. The media composed of metamaterials have tunable effective material parameters, and their electromagnetic response can be adjusted in real time. By using metamaterials as substrates or superstrates for antenna, significant improvements have been observed in the properties of the fractal antenna. In this paper, an effort is made to use the square split ring resonator (SRR) in conjunction with the fractal patch antenna to enhance the directivity, gain, voltage standing wave ratio (VSWR), and bandwidth at multiple resonant frequencies. To serve this purpose, two different types of tunable multiband micro-split metamaterial square SRR are loaded on the fractal
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