No abstract

Herein a dual-band wide-angle reflective circular polarization converter, based on a metasurface was developed. The unit cell is composed of a split square ring and a nested square patch. The split square ring plays the role of creating polarization conversion. The square patch is useful for improving the quality of axial ratio. It was verified that the structure could transform the x-polarized incident wave into left-hand circular polarization in the lower frequency band, and to right-hand circular polarization in the higher frequency band. For y-polarized incidence, the transformation has orthogonal modes to that for x-polarized incidence. Moreover, the 3 dB axial ratio takes place in the ranges of 8.42–12.32 GHz and 18.74–29.73 GHz, corresponding to a relative bandwidth of 37.61%, and 45.35%, respectively. In addition, the polarization conversion efficiency is greater than 99% in the ranges of 8.65–11.83 GHz and 19.55–29.36 GHz. Furthermore, for oblique incidence, the axial ratio remains stable, even at 50° incidence, for the lower frequency band. Lastly, a prototype is fabricated and measured for experimental verification. The measured and simulated results were in good agreement. Compared with other designs in the literature, the proposed converter operates with good performance in dual-band, with high-efficiency, and with angular stability.

An ultra-broadband angular-stable reflective linear to cross polarization converter based on metasurface is developed. The unit cell of the converter is formed by a slant end-loaded H-shaped resonator. The slant arrangement is to create polarization conversion. The end-loaded stubs are useful for miniaturization and the slots are responsible for enlarging bandwidth. The simulated results show that the polarization conversion ratio of the proposed design is better than 90% in the range of 9.83–29.37 GHz, corresponding to a relative bandwidth of 99.69%. It is also demonstrated that the mean polarization conversion ratio is larger than 80% even though the incident angle reaches 40° for both x-polarized and y-polarized incidences. To validate the design, a prototype of the proposed structure is fabricated and measured. Satisfactory agreement has been observed between measurement and simulation. Compared with the designs in the literature, the developed converter exhibits good performance of high efficiency, ultra-broadband and angular stability. Potential applications can be expected in polarization-controlled devices, stealth surfaces, antennas, etc.