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A Thin Double-Mesh Metamaterial Radome for Wide-Angle and Broadband Applications at Millimeter-Wave Frequencies

Antireflection has been a critical part in the design of optical and opto-electronic instruments. In the emerging millimeter (mm)-wave technology for the next-generation communication and autonomous driving, antireflection treatment is increasingly important due to the quasi-optical nature of electromagnetic waves at high frequencies. Enclosures that protect radar or communication phased arrays will introduce reflections if they are not designed properly. In this article, a novel metamaterial radome (meta-radome) is developed based on closely spaced metallic square meshes patterned on a thin dielectric substrate. We show that by deliberately employing the coupling between the meshes, the entire structure can be treated as a homogenized metamaterial slab with its wave impedance matched to that of free space. The resulting meta-radome can be optimized to have good transmission (> 90%) over an extremely wide range of angles of incidence (0° – 80°) for both transverse-electric (TE) and transverse-magnetic (TM) polarizations. Since the meta-radome is not resonant, it has a very small Ohmic loss and broad bandwidth. In addition, the proposed meta-radome is very easy to fabricate with standard fabrication techniques. Thus, it can be very attractive for many practical microwave and mm-wave applications.