In this paper, the application of gammadion chiral metamaterial for converting linearly polarized waves to circularly polarized waves is presented and using this a circular polarized antenna for wireless application is proposed. First of all, a traditional rectangular microstrip patch antenna has been designed at resonance frequency of 5.15 GHz, which gives linear polarization. The linearly polarized waves are allowed to feed gammadion chiral metamaterial, which is placed at a height of 33 mm above the reference antenna. The gammadion chiral metamaterial produces two special effects that are responsible for polarization rotation: circular dichroism and optical activity. As a result of these effects, the necessary conditions for circularly polarized radiation are fulfilled, and antenna is converted to the circularly polarized antenna. This method gets rid of designing of complicated feeding structure that is necessary for circular polarization. The role of gammadion chiral metamaterial to convert linear polarization to circular polarization has been described. The antenna is fabricated, and the measurement of return loss, axial ratio, etc. is also carried out. Simulation and measurement results agree with each other.
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