Omega-Bianisotropic Wire-Loop Huygens’ Metasurface for Reflectionless Wide-Angle Refraction

Laser-Drilled All-Dielectric Huygens’ Transmit-Arrays as 120 GHz Band Beamformers

“…Table 3 finally shows a comparison between the proposed structure and other Huygens' metasurface (HMS) designs at microwave frequencies, including metallic PCB-based as well as all-dielectric metasurfaces. The majority of metasurface designs in literature consist of two or more metallic layers on a dielectric and are fabricated using the standard PCB process [19], [46], [59]- [62]. On the other hand, all-dielectric designs at microwave frequencies are typically fabricated using CNC-machining [47], [63], with the proposed design being the first of its kind that uses laser-drilling to achieve high-precision fabrication.…”

“…The proposed laser drilled all-dielectric Huygens' transmit-array may thus represent an attractive alternate to a standard PCB based fabrication for passive antenna beam-forming above 100-GHz for beyond 5G communication networks. [60] Standard PCB process 4 9.4 to 10.6 GHz Beam-focusing [61] Standard PCB process 6 5.6 & 15 GHz Beam-focusing [62] Standard PCB process 2 20 GHz Beam-tilting [19] Standard PCB process 2 24 to 28 GHz Lens [46] Standard PCB process 2 58 to 63 GHz Beam-tilting, splitting & lens [52] Standard PCB process 3 83 GHz Lens [53] Standard PCB process 3 83 GHz Beam-tilting [63] All-dielectric CNC-machining 3 9 to 11 GHz Beam-tilting [47] CNC…”

Microwave Huygens’ Metasurfaces: Fundamentals and Applications

“…While the stacked-layer topology is more frequently utilized, the wire-loop unit cell topology can be regarded as a more direct and natural implementation of the boundary conditions. As a set of both electric and magnetic currents are required to achieve arbitrary wave transformations, a wire-loop structure is able to represent these currents directly [9], [21], [34]. Specifically, an electric wire serves to produce and control the desired electric current, while an electric loop controls an effective orthogonal magnetic current.…”

“…2(a) [9]. However, to align the direction of the electric and magnetic dipole moments with the wire and loop, cuts of the metasurface need to be placed in a stacked manner [9], [34]. Unfortunately, such complicated assembly can lead to increased difficulties of realizing such designs.…”

“…As discussed previously, bianisotropy can lead to remarkable effects such as polarization and asymmetric matching with chirality and Omega-bianisotropy respectively. Thus, as exploration of bianisotropic metasurface applications expanded, Omegabianisotropic versions of the wire-loop topology also emerged [34], [35]. As discussed with the stacked-layer topology, it was shown that asymmetry of the unit cell can be utilized to realize Omega-bianisotropy.…”