A Magnetic-Enhanced Reflectarray Antenna for High-Power Microwave Applications

A magnetic-enhanced reflectarray antenna (MERA) based on
$\varepsilon $
-negative (ENG) metamaterial is proposed in this communication. By utilizing the variable-rotation technique (VRT), the MERA achieves the first-ever application of the ENG metamaterial in a high-power microwave (HPM) reflectarray antenna (RA) under passive conditions. The antenna element of the MERA is a tri-layer structure composed of an ENG layer sandwiched by two high-
$\varepsilon _{\text {r}}$
dielectric slabs, with a metal sheet situated at the bottom of the sandwich structure to reflect incident waves. Operating in X-band (8.6–9.8 GHz), the MERA element exhibits a continuous 360° phase coverage with negligible element loss and robustness against the incident angle, with an estimated power handling capacity (PHC) exceeding 1 GW/m2. Using the proposed element, a prototype focused in the direction of (
$\theta _{0}= 20^{\circ }$
,
$\varphi _{0}=0^{\circ }$
) was fabricated and experimented, and the simulation results were found to be in good agreement with the measured results. The measured results indicate that the MERA has an aperture efficiency greater than 53.4% within the operation bandwidth, with the maximum value reaching 64.33%, while achieving sidelobe levels of less than −20 dB.