A compact dual-band filtering metasurface antenna based on characteristic mode analysis

Abstract

In this paper, a compact dual-band filtering metasurface antenna (MSA) based on characteristic mode analysis (CMA) is proposed. The modal characteristics of the proposed filtering MSA are studied by using the CMA. Two types of modes with maximum radiation field (the radiation mode) and zero radiation field (the radiation null mode) in the specific direction are chosen as excitation modes. Furthermore, shorting pins are introduced to make the radiation null mode better excited. After the feeding point is optimized, a dual-band filtering MSA with four radiation nulls can be realized. A filtering MSA with a compact size (0.41λ0 × 0.41λ0) operating at 7.35/8.78 GHz is designed and fabricated. The measured peak gain and 10 dB bandwidth at the low band (high band) are 6.77 dBi (7.1 dBi) and 8.03% (2.73%). The measured inner stopband suppression is larger than 17 dB and lower stopband suppression is more than 18 dB.