Triple Band Reflective Metasurface Based Linear to Circular Polarization Converter

Converting the polarization of electromagnetic waves from linear to circular is required for many microwave applications. This article discusses the use of metasurface MS based reflective surface for converting the polarization from linear to circular. A new MS element is proposed to manipulate the phase, amplitude, and polarization of waves. It consists of two tilted and crossed bi-directional metallic arrows with elliptical ring. By applying two small slits in the long arrow, the operating bandwidth of the proposed structure is significantly increased. The geometrical dimensions of this MS reflective element are chosen so that the magnitudes of the co-polarized and cross-polarized reflected wave components are nearly equal while maintaining a ±90 degree phase difference. Linear to dual circular polarization conversation has been achieved at three frequency bands. The simulated results show that right hand circular polarized (RHCP) waves can be sensed in 14.1-15.8 GHz and 25.2-41.5 GHz while the left hand circular polarized wave (LHCP) can be observed from 45.75 to 49 GHz with y-polarized incident wave. The proposed MS structure has a high energy conversation efficiency (ECE) above 98%. For more validation a $20\times 20$ MS elements arranged in two-dimensional rectangular lattice and simulated to verify the results of the single element. Moreover, the polarization conversion ratio (PCR) is calculated beside the circular polarization conversion ratio, ellipticity and elliptical angle to detect the direction of the reflected CP wave.