Ultrathin Dual Polarization Huygens’ Element With Broadband Electric and Magnetic Resonance Modes Degeneracy for Ka-Band Conformal Lens Antenna

An ultrathin dual polarization Huygens’ element (HE) is proposed based on a novel degeneracy method for electric and magnetic resonance modes. This HE exhibits a wider operation bandwidth (BW) and higher transmittance than the other hole-free dual-polarization lens antenna (LA) elements of similar thickness. By arranging three pairs of bilayer-dipole-pairs (BDPs) in parallel, the element achieves electric and magnetic resonance modes at the same frequency. In addition, the mutual coupling between the electric and magnetic resonance modes is effectively eliminated by implementing a reverse translation of the BDPs located at the edge of the element. The approach facilitates the realization of dual polarization Huygens’ resonance by combining two orthogonal BDPs. The proposed method eliminates the requirement for substrate thickness as the degree of freedom, enabling the element to achieve Huygens’ resonance even with an ultrathin substrate thickness as low as
$0.05\lambda _{0}$
(where
$\lambda _{0}$
is the free space wavelength). Furthermore, a cylindrical conformal LA operating in the Ka-band is designed based on this proposed HE. Due to the presence of broadband magnetoelectric degeneracy in the HE, the proposed LA prototype exhibits a wider gain BW compared to other conformal LAs with similar thicknesses. Moreover, the LA prototype achieves an aperture efficiency (AE) exceeding 30% due to the high transmittance provided by the proposed HE.