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.