This paper presents the exact closed-form solution for a new planar lens, hereinafter referred to as Reflecting Luneburg Lens (RLL). The proposed structure consists of two stacked parallel plate waveguides of circular shape. The rays generated by a point source located at the periphery of the bottom waveguide propagate along curvilinear paths, whose trajectories result from a variable refractive index profile with azimuthal symmetry. Then, these rays encounter a reflecting boundary and emerge all parallel in the upper uniform waveguide. The behavior of this lens resembles that of a flat Luneburg lens, with the fundamental difference that it works in reflection. The exact refractive index profile is found by solving the non-linear integral equation of ray-congruence trough a truncated Abel transform method. The concept is numerically verified through different implementations of the effective refractive index profile, including a metasurface-based implementation. The proposed lens triggers new possibilities that the normal flat Luneburg lens does not offer, and it is applicable in a large variety of microwave, terahertz and optical devices.

Ruiz-Garcia, J., Martini, E., Giovampaola, C.D., Gonzalez-Ovejero, D., Maci, S. (2021). Reflecting Luneburg Lenses. IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 69(7), 3924-3935 [10.1109/TAP.2020.3044668].

Reflecting Luneburg Lenses

Martini, Enrica
Membro del Collaboration Group
;
Maci, Stefano
Membro del Collaboration Group
2021-01-01

Abstract

This paper presents the exact closed-form solution for a new planar lens, hereinafter referred to as Reflecting Luneburg Lens (RLL). The proposed structure consists of two stacked parallel plate waveguides of circular shape. The rays generated by a point source located at the periphery of the bottom waveguide propagate along curvilinear paths, whose trajectories result from a variable refractive index profile with azimuthal symmetry. Then, these rays encounter a reflecting boundary and emerge all parallel in the upper uniform waveguide. The behavior of this lens resembles that of a flat Luneburg lens, with the fundamental difference that it works in reflection. The exact refractive index profile is found by solving the non-linear integral equation of ray-congruence trough a truncated Abel transform method. The concept is numerically verified through different implementations of the effective refractive index profile, including a metasurface-based implementation. The proposed lens triggers new possibilities that the normal flat Luneburg lens does not offer, and it is applicable in a large variety of microwave, terahertz and optical devices.
2021
Ruiz-Garcia, J., Martini, E., Giovampaola, C.D., Gonzalez-Ovejero, D., Maci, S. (2021). Reflecting Luneburg Lenses. IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, 69(7), 3924-3935 [10.1109/TAP.2020.3044668].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/1124670