Ultra-wideband linear-to-circular polarization converter with ellipse-shaped metasurfaces

Abstract

Generally, a traditional method to generate circularly polarized waves faces limitations like the narrow band, bulky volume and low efficiency. In this paper, a linear-to-circular (LTC) polarization converter based on metasurface with high efficiency and maneuverable ultra-wideband is proposed. By utilizing the ellipse-shaped structure on reflective metasurface, the LTC polarization converting condition can be achieved at four closer frequencies, leading to a quite wide frequency band. The simulated results show that the axial ratio of the reflective circularly polarized wave is lower than 3 dB within the frequency band of 10.21–24.97 GHz, and a relative band reaches above 83.91%. Furthermore, the bandwidth of the polarization conversion can be sustained from 10.21 to 22.71 GHz at incident an angle of 48°. The electrical field and current flows are given to analyze the circular polarization performance. For validation, a sample is fabricated and measured; measured results and simulated results coincide with each other. The proposed LTC polarization converter is easy in terms of design and fabrication complexity, showing promising potentials in real-world circularly polarized wave generator applications.