Broadband Flat-Lens Antenna Design Using Ultrathin Huygens’ Metasurface for Millimeter-Wave Applications
Zohre Pourgholamhossein, Mahmoud Niroo Jazi, Tayeb A. Denidni
Abstract
This communication presents a novel ultrathin wideband metasurface (MTS)-based flat-lens antenna with high aperture efficiency and high-gain responses, which also addresses the problems of large volume, high weight, and narrow bandwidth. The proposed Ka-band (26.5–30.77 GHz) antenna is designed based on the surface electric and magnetic impedances acquired from Huygens’ principle. This design aims to expand the antenna bandwidth by using a double-layer MTS structure as thin as <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> /21, where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> is the free-space wavelength at the central frequency of 28 GHz. To estimate its performance, the proposed antenna is fabricated and measured. The experimental results show that the antenna gain is at least 13.2 dB greater than its feed with a peak value of 29.5 dBi at 27.4 GHz. In addition, 1 dB gain antenna bandwidth of 6.6% and a 3 dB gain bandwidth of 15% are achieved. The sensitivity of the proposed unit cells to fabrication errors and the effect of oblique incidence are also studied.