Design of Single-Layer Metasurface Filter by Conformational Space Annealing Algorithm for 5G mm-Wave Communications

Abstract

In this paper, we first demonstrate a metasurface that offers spectral filter performances not yet reported for a single-layer metasurface because of the limited number of geometric parameters. The configuration of the metasurface is determined by a conformational space annealing algorithm, which is a key toward being able to design for a desired frequency, bandwidth, and response type for various wireless communication devices, including the fifth-generation (5G) millimeter-wave communication devices. As a proof-of-concept, we fabricate a very thin ( $50~\mu \text{m}$ ) single-layer metasurface combined with a 5G antenna array to experimentally demonstrate high frequency-selectivity with stable frequency responses with oblique incidences and polarizations. The gain of the $4\times {4}$ patch antenna array with the metasurface bandpass filter was reduced by only 0.48 dB compared with that of the $4\times {4}$ patch antenna array itself at 27.5 GHz, whereas the gain of the $4\times {4}$ patch antenna array with the metasurface bandstop was reduced by 20 dB compared with that of the $4\times {4}$ patch antenna array itself at 28.5 GHz.