Abstract
In this work, a metasurface with the symmetrical double C-shaped narrow ring connected with the central cross structure is investigated by simulation, theory and experiment, which can near-perfectly convert linearly polarized electromagnetic waves into their orthogonal components in the frequency ranges from 9.38 to 13.36 GHz and 14.84 to 20.36 GHz. And the corresponding fractional bandwidths within the two bands are 35.00% and 31.36%, respectively. The influences of structural parameters on the polarization conversion performance are studied. The results show that the central frequencies and bandwidths of the two bands can be easily modulated by varying the structural parameters of r and θ . The high-efficiency and dual-broadband characteristics can also be well maintained in the oblique incidence range of 0–45°. Meanwhile, the mechanisms of polarization conversion are analysed, and several formulas are used to calculate the reflection coefficients of the co- and cross-polarization under the normal incident y -polarized electromagnetic waves based on the phase difference of the reflection coefficients of the u - and v -polarized conversions. The experiment results are in good agreement with those of simulations and theoretical analysis. The proposed metasurface has important applications in novel polarization control devices.
Highlights
Metasurface is a sort of artificial two-dimensional material containing periodic or aperiodic subwavelength units, possessing unique characteristics of manipulating electromagnetic (EM) waves [1]–[5]
polarization conversion ratios (PCR) is described for characterizing the performance of polarization converters, and it is expressed as: PCR = rxy 2/ rxy 2 + ryy 2 (1)
In the second frequency band (14.84–20.36 GHz), the PCR is higher than 99.32%, and the bandwidth is 5.29 GHz
Summary
Metasurface is a sort of artificial two-dimensional material containing periodic or aperiodic subwavelength units, possessing unique characteristics of manipulating electromagnetic (EM) waves [1]–[5]. Hao et al [26] designed a linear polarization converter using anisotropic metamaterial with I-shaped structure. Grady et al described a broadband ultrathin metamaterial with a multilayered structure for linear polarization conversion in the range of 0.52 to 1.82 THz [32]. A perfect and dual-broadband linear polarization converter is theoretically proposed and experimentally demonstrated. Four resonances occur within the 9.38–13.36 GHz and 14.84–20.36 GHz frequency ranges In these dual-band ranges, x-polarized or y-polarized incident waves can almost be completely converted into corresponding cross-polarized waves. The proposed metasurface has advantages of simple geometric structure, high efficiency and wide bandwidth comparing with the previous designs [33], [34], exhibiting great application potential in polarization control devices
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