A Low-Profile Wideband Tightly Coupled Dipole Array With Reduced Scattering Using Polarization Conversion Metamaterial

A novel approach aimed at reducing the out-of-band scattering cross section (SCS) and preserving the radiation characteristics of a low-profile wideband tightly coupled dipole array (TCDA) operating in P-L band is presented. The array is designed without wide-angle impedance matching (WAIM) layers for low profile and simple topological structure. The SCS reduction of the proposed TCDA is achieved by loading the array with polarization conversion metamaterial (PCM). The PCM is arranged in a chessboard configuration and placed on the ground plane of the TCDA. The infinite array is able to achieve a 4:1 bandwidth from 0.5 to 2.0 GHz, with VSWR <2.5 for scanning up to ±60° in the E-plane and VSWR <3.0 for scanning up to ±45° in the H-plane, respectively. An $8 \times 8$ TCDA prototype is fabricated and measured. The experimental results are in good agreement with simulated results. The simulated and experimental results demonstrate that by using the proposed approach with PCM, the monostatic SCS is significantly reduced within 6.0–18.0 GHz under normal incidence. Meanwhile, the radiation characteristics are well preserved in the operating band of the TCDA.