Wideband metasurface reflective linear-cross and linear-circular meander-line polarizer for WLAN and SatCom applications in S and C bands

Abstract

The wideband multipurpose metasurface polarizer described in this article can convert linearly-polarized (LP) waves to cross-polarized (CLP) and circularly-polarized (CP) waves in S and C band applications. To achieve the desired polarization conversion, a meander-line with a non-uniform width unitcell is carved on a FR4-substrate. An airgap is then introduced between the dielectric and metal ground. Due to variations in the electrical length that the electromagnetic wave travels through the metasurface, this airgap is essential in determining whether the polarizer is a half- or quarter-waveplate. When the airgap was 9 mm, it was possible to record wideband LP-to-CLP at 2.87–7.12 GHz with a polarization conversion ratio (PCR) >90% and narrowband LP-CP at 2.45–2.69 GHz and 7.56–8.1 GHz with an axial-ratio (AR) <3 dB. By reducing the gap to 4.2 mm, the above band exhibits a wideband LP-CP conversion within bands of 3.02–3.35 GHz and 3.82–7.42 GHz with an incidence angle variation up-to 40°. Also, 3.18–3.33, 5.28–6.70, and 7.72–7.96 GHz bands exhibit PCR >90% over 40°. Surface impedance, surface current, and the transfer matrix technique were all used in the investigation of the conversion process for both normal and oblique incidence. RCS reduction, one of the applications, was also demonstrated.