Design and Characterisation of All-Dielectric Metasurface Reflector for mmWave Antennas

Abstract

This study presents the design, characterisation and prototyping of a novel all-dielectric artificial magnetic conductor (AMC) operating at 77 GHz. Unlike traditional metallic or hybrid counterparts, the proposed AMC is fabricated entirely from a commercial dielectric substrate, offering a low-loss and low-profile solution ideal for integration into compact antenna systems. The proposed AMC demonstrates strong reflection magnitude and achieves a 0° reflection phase at the targeted operating frequency. The −1-dB reflection bandwidth is 3.6 and 8.2 GHz for ± 45° and ± 90° phase windows, respectively. Integration with a dipole antenna confirms that the AMC maintains reflection phase stability under placement and fabrication tolerances. Measured results using a commercial material characterisation kit align closely with simulations, with deviations primarily attributed to substrate anisotropy at 77 GHz. Additionally, two alternative all-dielectric reflectors with high reflection magnitudes and nonzero reflection phases at 77 GHz are presented to support broader millimetre wave scenarios where in-phase reflection is nonessential. This work is among the first to report an all-dielectric AMC operating at millimetre wave frequencies while providing experimental validation, insights into anisotropy effects, fabrication constraints and real-world integration.