A Highly Efficient Method for Designing Bisymmetric P-B Phase Element Patterns of Coding Metasurfaces

The conventional trial-and-error method employed in the element pattern design of coding metasurfaces lacks theoretical guidance and requires considerable time and computational resources. To overcome this problem, this paper proposes a highly efficient design method for bisymmetric Pancharatnam-Berry (P-B) phase element patterns. First, the equivalent impedances of the element patterns are derived from the expected reflectance and frequency range using the transmission matrix method. Subsequently, the optimal geometric parameters of the element patterns are obtained using the equivalent circuit model. For the same element pattern, the time consumption is reduced by more than 25 times compared with that required for a single full-wave simulation. The simulation results show that metasurfaces adopting various design element patterns and the same coding sequence exhibit excellent backscattering energy homogenization performance, with a radar-cross-section reduction (RCSR) of less than -10 dB in the 9.47-17.57 GHz band. Two types of metasurfaces are fabricated using a meshed pattern, a sodium-calcium glass and a metallic mesh. The measured RCSR is less than -10 dB for a broadband of 7.74 GHz, and the normalized optical transmittance is 85% within 380-2500 nm, which is favorable for optical windows used in aerospace, medical, and precision instrumentation.

Automated summary

The conventional trial-and-error method in coding metasurfaces lacks theoretical guidance and is time-consuming and computationally expensive. This paper proposes an efficient design method for bisymmetric Pancharatnam-Berry (P-B) phase element patterns. The method derives the equivalent impedances of the element patterns and obtains the optimal geometric parameters using an equivalent circuit model. The simulation results demonstrate excellent backscattering energy homogenization performance in the 9.47-17.57 GHz band, with a radar-cross-section reduction (RCSR) of less than -10 dB.