Maxwell Fish-Eye and Half-Maxwell Fish-Eye Based on Graded Photonic Crystals

Gaufillet, Fabian; Akmansoy, É.

doi:10.1109/jphot.2018.2835157

Cited by 8 publications

(5 citation statements)

References 35 publications

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“…In optics, Maxwell fish-eye lenses [43], Luneburg lenses [44], Eaton lenses [45] and invisible lenses [43] are all spherical layered media. In astronomy, planetary atmospheres involved in ground-based astro-geodetic observations and atmospheric occultations observations are often modeled as spherical stratified media [46].…”

Section: B Discussionmentioning

confidence: 99%

General Formulas of Effective Earth Radius and Modified Refractive Index

Feng

Huang

2021

IEEE Access

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The effective earth radius can transform the curved ray path into a straight line, and the modified refractive index can transform the spherical ground into a plane. Using them can simplify the propagation modeling of electromagnetic waves in the atmosphere, so they are widely used in the calculation of long-range propagation of electromagnetic wave, and adopted by the ITU Recommendations and the IEEE Standards. In this paper, upon employing simple geometric methods, we provide general formulas for the effective earth radius and the modified refractive index, pointing out that they both originate from the use of conformal transformations. In turn, we prove that for both quantities the formulas contained in the ITU Recommendations and the IEEE Standards are special cases of the general formulas given in this paper. Our results provide a solid mathematical background to the concepts of effective earth radius and modified refractive index, and pave the way for their use beyond the propagation of electromagnetic waves in the earth atmosphere, e.g. to the propagation of other types of waves in generic media.INDEX TERMS Effective earth radius, modified refractive index, conformal transformation, wave propagation, ray tracing.

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Section: B Discussionmentioning

confidence: 99%

General Formulas of Effective Earth Radius and Modified Refractive Index

Feng

Huang

2021

IEEE Access

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“…The geometry of the lenses is determined by the required antenna parameters such as gain, directivity, focal distance, beam width, dielectric permittivity of materials used in the component, size of the device and so on [15]. Depending on these parameters, lenses can be classified as spherical (for example Luneburg [16] or Maxwell's fish-eye lens [17]), hyperbolical [18], hemispherical [19], [20], elliptical [21], bullet [22], or cylindrical [23] shaped. These devices are typically placed close to the antenna element, e.g., on-chip antennas, or may be integrated on the chassis of the device as well.…”

Section: Introductionmentioning

confidence: 99%

An Ultralow-Loss and Lightweight Cellulose-Coated Silica Foam for Planar Fresnel Zone Plate Lens Applications in Future 6G Devices

Kokkonen

Pálvölgyi

Śliz

et al. 2023

Antennas Wirel. Propag. Lett.

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Several passive components of fifth-generation (5G) and future sixth-generation (6G) telecommunication devices require substrate materials of very low dielectric permittivity and losses to avoid wave absorption, reflection, and interference. Apart from their dielectric properties, these materials shall be also affordable and sufficiently robust to enable postprocessing and integration of functional electrical components. Herein, we demonstrate a Fresnel zone plate lens for operation at 300 GHz, whose structure is supported on substrate made of an ultraporous silica foam with a nanocellulose thin film coating. The effective dielectric permittivity and loss of the substrate (ε r = 1.018 ± 0.003 and tan δ < 3 × 10 −4 at 300 GHz) is close to that of air. Experiments show that the fabricated Fresnel zone plate lens connected to a waveguide with total gain of 20 dB and angular beamwidth of 2.9°in good agreement with microwave simulations. The proposed lens structure has additional advantages such as small volume, ultralight weight, and simulations indicate 60 GHz bandwidth making it particularly appealing for radio front-ends of future 6G devices.

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“…Distant object tracking is an important application of Fresnel lenses [1][2][3]. The lens is also used to form precise visual images [4][5][6][7], even with a varying focal distance [8], for Image rectification [9], signal enhancement [10], imaging systems [11], lens distortion models [12], and other applications [13,14]. Different methods have been proposed for designing focusing lenses, including flat focusing Fresnel structures.…”

Section: Introductionmentioning

confidence: 99%

Microprismatic Fresnel Lens for Formation of Uniform Light Circle

Antonov

Manko

et al. 2021

IEEE Photonics J.

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Focusing Fresnel lenses are used in many fields of applied optics. These devices are used in optical sensor systems for imaging and optoelectronic integration. The traditional Fresnel lens concentrates the light intensity on the center of the formed image. We present a microprismatic Fresnel lens that transforms a circular incident parallel light beam into a homogeneous light circle with the necessary diameter at a certain distance from the lens. These transforming Fresnel concentrators can be successfully used, for example, in monitoring devices to automatically adjust the output signal from four-quadrant photodetectors. Traditional focusing Fresnel structures are manufactured by photolithographic methods or adjustable direct laser recording with photoresists. These methods enable the formation of stepped optical structures, which have inherent surface defects, resulting in the formation of images that are not high in quality. The proposed specialized Fresnel concentrators can be easily fabricated via the diamond cutting method, which enables the manufacturing of flat working surfaces with exceedingly high optical quality. We also develop a method for simulating the Fresnel transforming lenses as flat conical working facets and calculate the geometric parameters of the circular concentrators. We then feed the simulation results to the diamond cutting method and fabricate the microprismatic light transforming samples. These samples are then investigated experimentally with a collimated laser beam. The obtained data agree with the theoretical predictions.

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Maxwell Fish-Eye and Half-Maxwell Fish-Eye Based on Graded Photonic Crystals

Cited by 8 publications

References 35 publications

General Formulas of Effective Earth Radius and Modified Refractive Index

General Formulas of Effective Earth Radius and Modified Refractive Index

An Ultralow-Loss and Lightweight Cellulose-Coated Silica Foam for Planar Fresnel Zone Plate Lens Applications in Future 6G Devices

Microprismatic Fresnel Lens for Formation of Uniform Light Circle

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