Low-Scattering Broadband Phased Array With Polarization-Selective Metasurface Using Characteristic Mode Analysis

Based on periodic characteristic mode analysis (PCMA), a low-scattering broadband phased array with polarization-selective metasurface (PSM) is proposed. By adjusting the characteristic modes that dominate the reflection phase under cross-polarized normal incident waves, two types of array elements with comparable radiation characteristics but a 180° reflection phase difference are developed. The PSM structure is systematically designed based on the analysis of modal currents and modal significances, involving elongated rectangular patches and dielectric layers. Two broadband phased arrays, namely, the proposed array and the reference array, are developed. Both antenna arrays are designed to operate within the 6–18-GHz frequency range and achieve scanning capabilities of up to 60° in the E-/H-planes. Prototypes of the proposed and reference arrays are fabricated and measured. The results obtained from both the measurements and simulations confirm the effectiveness of the low-scattering antenna array design, thereby verifying the practicality of PCMA. Compared to the reference array, the proposed array achieves more than 10 dB monostatic radar cross section (RCS) reduction in both in-band (6–18 GHz) and out-of-band (18–24 GHz) frequency ranges without any loss in gain.