Novel Dual-Band Metascreen for Dual-Band Near-Field Phase Correction

This article proposes a new dual-band metascreen (DBM), also known as a fishnet metasurface, for polarization-independent near-field phase corrections. The DBM is based on quad-layer phase-shifting cells with two interlaced slot patterns, one at the center and the other at the corner of the cells, to cater to lower and higher operating frequencies simultaneously. A mechanism is devised to find optimal cells with the desired phase pairs at the two frequencies, and slots are arranged with a strategy to achieve the desired results with DBM. We also propose the first-ever dual-band metallic, partially reflective surface to develop a dual-band directive antenna. A prototype of a
$5.6\lambda _{L}$
circular-shaped DBM and feed antenna operating in the Ku-band is tested experimentally to verify the proof of concept. Around the lower and higher bands’ center frequencies, the impedance bandwidths are 600 and 1800 MHz, respectively. Excellent radiation performances are achieved with a peak directivity of 20.3 and 18.8 dBi at 11.9 and 14.4 GHz, respectively. The DBM is about
$0.72\lambda _{L}$
thick and weighs only 56 g. Including the feed, the overall antenna profile is around
$1.5\lambda _{L}$
. The proposed antenna’s conspicuous features make it suitable for cost-effective end-user solutions requiring low-profile, lightweight, and highly directive dual-band high-gain antennas.