Design Formulas for Flat Gradient Index Lenses with Planar or Spherical Output Wavefront

Journal article (2024)

Authors

Weiya Hu Student
C.M. Coco Martin Tera-Hertz Sensing - EEMCS
D. Cavallo Tera-Hertz Sensing - EEMCS
Research Group
Tera-Hertz Sensing (EEMCS) (TU Delft)
Ray tracing Lens antennas Geometrical optics Optical design Gradient indexes lenses
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Published Date

2024

Language

English

Reuse Rights

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Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Tera-Hertz Sensing

Abstract

A semi-analytical method is presented for the design of gradient index (GRIN) flat lenses. Closed-form expressions are derived to define the refractive index distribution of the lens, for several cases: collimating lenses with on-axis feed, collimating lenses with off-axis feed, lenses converting spherical wavefronts with different wavenumbers, lenses changing the focal number of a quasi-optical system, and Fresnel zone lenses. The design equations are validated by ray-tracing simulations in inhomogeneous media, implemented by numerical solution of the Eikonal equation.