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11 pages, 2244 KB

Open AccessArticle

Research on the Optical Receiving Performance of Underwater Wireless Optical Communication System Based on Fresnel Lens

by Ya Zhao, Shixiang Hong, Zhanqi Zhang, Xiaoxuan Zhu and Peng Zhang

Photonics 2025, 12(10), 1010; https://doi.org/10.3390/photonics12101010 - 13 Oct 2025

Cited by 1 | Viewed by 1009

In response to the practical demands of high rate, long distance, low cost and miniaturized equipment for underwater wireless communication, an underwater wireless optical communication experimental system with Fresnel lenses as optical receiving antennas has been established. Using 488 nm and 520 nm [...] Read more.

In response to the practical demands of high rate, long distance, low cost and miniaturized equipment for underwater wireless communication, an underwater wireless optical communication experimental system with Fresnel lenses as optical receiving antennas has been established. Using 488 nm and 520 nm lasers as the test light sources, the relationship curves between the focusing performance of several Fresnel lenses with different light transmission aperisions and focal lengths after passing through the underwater channel and the lens surface, laser wavelength, and incident angle were obtained. The influence of the laser incident angle on the focusing spots of 488 nm and 520 nm lasers was measured. The experimental results indicate that the Fresnel lens exhibits excellent light concentration performance, with the overall system concentration efficiency being higher than that of conventional lenses, significantly enhancing the received optical power in underwater wireless optical communication systems. Additionally, configuring the sawtooth surface as the incident surface of the Fresnel lens can improve the concentration efficiency by approximately 1% to 5% compared to using a smooth incident surface. Full article

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15 pages, 14339 KB

Open AccessArticle

Origami Fresnel Zone Plate Lens Reflector Antennas for Satellite Applications

by Massimo Donelli, Sreedevi Menon, Viviana Mulloni, Giada Marchi and Irene Dal Chiele

Electronics 2025, 14(19), 3892; https://doi.org/10.3390/electronics14193892 - 30 Sep 2025

Cited by 2 | Viewed by 1209

Abstract

This work presents a methodology for designing deployable reflector antennas that combine origami structures and the Fresnel zone plate lens to obtain a compact antenna structure. In particular, Miura and Yoshimura’s origami patterns have been considered for the design of the Fresnel reflector [...] Read more.

This work presents a methodology for designing deployable reflector antennas that combine origami structures and the Fresnel zone plate lens to obtain a compact antenna structure. In particular, Miura and Yoshimura’s origami patterns have been considered for the design of the Fresnel reflector mirror and the conical horn antenna feeder, respectively. A set of memory-form alloy (MFA) actuators have been used to deploy the antenna. The MFA actuators are activated by a direct current aimed at increasing the temperature and activating the memorized shape. The combination of these techniques provides light, inexpensive, and very compact antennas, particularly suitable for satellite applications. A numerical and experimental assessment campaign has been carried out on antenna prototypes operating in the

K_{u}

band at 15 GHz. The obtained experimental results are quite promising. Full article

(This article belongs to the Special Issue Theory, Methods and Applications of Electromagnetic Scattering)

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9 pages, 2795 KB

Open AccessArticle

A Polydimethylsiloxane (PDMS) Transparent Fresnel Zone Lens Antenna at Ku-Band for Satellite Communication

by Massimo Donelli, Sreedevi Menon, Viviana Mulloni, Giada Marchi and Irene Dal Chiele

Electronics 2025, 14(19), 3766; https://doi.org/10.3390/electronics14193766 - 24 Sep 2025

Cited by 1 | Viewed by 813

Abstract

This work presents the design of a transparent Fresnel-zone lens antenna fabricated from Polydimethylsiloxane, also known as PDMS or dimethicone, a polymer widely used for manufacturing and prototyping microfluidic chips. The antenna operates in the

K_{u}

band at 15 GHz. Specifically, a [...] Read more.

This work presents the design of a transparent Fresnel-zone lens antenna fabricated from Polydimethylsiloxane, also known as PDMS or dimethicone, a polymer widely used for manufacturing and prototyping microfluidic chips. The antenna operates in the

K_{u}

band at 15 GHz. Specifically, a 3D-printed polylactic acid (PLA) mold is created and filled with PDMS to obtain the lens structure. The PLA mold can be used multiple times to produce different lens prototypes. An antenna prototype has been designed, fabricated, and assessed numerically and experimentally, demonstrating the capabilities and potential of the proposed design and production methodology. Full article

(This article belongs to the Section Microwave and Wireless Communications)

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15 pages, 7237 KB

Open AccessArticle

New Design Scheme for and Application of Fresnel Lens for Broadband Photonics Terahertz Communication

by Peng Tian, Yang Han, Weiping Li, Xiongwei Yang, Mingxu Wang and Jianjun Yu

Sensors 2024, 24(23), 7592; https://doi.org/10.3390/s24237592 - 27 Nov 2024

Cited by 7 | Viewed by 3288

Abstract

In terahertz communication systems, lens antennas used in transceivers are basically plano-convex dielectric lenses. The size of a plano-convex lens increases as the aperture increases, and thinner lenses have longer focal lengths. Through theory and simulation, we designed a Fresnel lens suitable for [...] Read more.

In terahertz communication systems, lens antennas used in transceivers are basically plano-convex dielectric lenses. The size of a plano-convex lens increases as the aperture increases, and thinner lenses have longer focal lengths. Through theory and simulation, we designed a Fresnel lens suitable for the terahertz band to meet the requirements of large aperture and short focal length, and simulated the performance, advantages, and disadvantages of the terahertz Fresnel lens. A 300 GHz terahertz wireless communication system was built to verify the gain effect of the Fresnel lens antenna. The experimental results demonstrate that the Fresnel lens can be used for long-distance terahertz communication with larger aperture diameters, overcoming the limitations of traditional plano-convex lenses. The theoretical gain of a 30 cm Fresnel lens is 48.83 dB, while the actual measured gain is approximately 45 dB. Full article

(This article belongs to the Section Optical Sensors)

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12 pages, 5499 KB

Open AccessCommunication

Design of Moiré-Inspired Metasurface Lens for Focusing Electromagnetic Power in Fresnel Near-Field Region

by Tae-Heung Lim, Hyunsoo Kim, Chulhun Seo and Hosung Choo

Energies 2022, 15(11), 3911; https://doi.org/10.3390/en15113911 - 25 May 2022

Cited by 3 | Viewed by 3525

Abstract

This paper proposes a Moiré-inspired metasurface lens system to focus electromagnetic power in the Fresnel near-field region. The proposed metasurface lens (MSL) system is composed of two MSLs and a square patch antenna source. The MSLs are modeled based on the transmit phase [...] Read more.

This paper proposes a Moiré-inspired metasurface lens system to focus electromagnetic power in the Fresnel near-field region. The proposed metasurface lens (MSL) system is composed of two MSLs and a square patch antenna source. The MSLs are modeled based on the transmit phase distributions of Moiré lens theory, and each unit cell structure (patch shape and Jerusalem cross slot shape) is determined to fit the calculated transmit phase distributions at each location. When changing the unit cell structure, phase and transmittance variations are achieved over 330° and −3 dB. The square patch antenna source is then designed to excite the field to the MSLs. The measured reflection coefficients are below −10 dB at 5.8 GHz while rotating the second MSL. The focal length can be adjusted from a minimum of 38 cm to a maximum of 110 cm according to the rotation angle of the second MSL. The proposed MSL system can be employed for wireless power transmission applications to focus electromagnetic power at various locations in the near-field region. Full article

(This article belongs to the Special Issue Next Generation Wireless Charging System for Mobile Devices)

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Graphical abstract

16 pages, 30389 KB

Open AccessArticle

Charging Mobile Devices in Indoor Environments

by Diogo Matos, Ricardo A. M. Pereira, Helena Ribeiro, Bernardo Mendes, Daniel Belo, Arnaldo Oliveira and Nuno Borges Carvalho

Energies 2022, 15(9), 3450; https://doi.org/10.3390/en15093450 - 9 May 2022

Cited by 8 | Viewed by 3531

Abstract

Wireless power transfer promises to revolutionize the way in which we use and power mobile devices. However, low transfer efficiencies prevent this technology from seeing wide scale real-world adoption. The aim of this work is to use quasioptics to develop a system composed [...] Read more.

Wireless power transfer promises to revolutionize the way in which we use and power mobile devices. However, low transfer efficiencies prevent this technology from seeing wide scale real-world adoption. The aim of this work is to use quasioptics to develop a system composed of a dielectric lens fed by a phased array to reduce spillover losses, increasing the beam efficiency, while working on the antenna system’s Fresnel zone. The DC-RF electronics, digital beamforming and beam-steering by an FPGA, and radiating 4 × 4 microstrip patch phased array have been developed and experimented upon, while the lens has been designed and simulated. This paper details these preliminary results, where the phased array radiation pattern was measured, showing that the beam is being generated and steered as expected, prompting the lens construction for the complete system experimentation. Full article

(This article belongs to the Special Issue Next Generation Wireless Charging System for Mobile Devices)

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11 pages, 2593 KB

Open AccessFeature PaperArticle

Polarization-Insensitive Unit Cells for a Cost-Effective Design of a 3-D-Printed Fresnel-Lens Antenna

by Salvador Moreno-Rodríguez, Miguel A. Balmaseda-Márquez, Javier Carmona-Murillo and Ángel Palomares-Caballero

Electronics 2022, 11(3), 338; https://doi.org/10.3390/electronics11030338 - 23 Jan 2022

Cited by 6 | Viewed by 4192

Abstract

A 3-D printed Fresnel-lens antenna formed by dielectric unit cells insensitive to polarization is presented in this article. The proposed unit cell can be implemented in any azimuth orientation, simplifying the design and the implementation of the Fresnel subzones, which is an advantage [...] Read more.

A 3-D printed Fresnel-lens antenna formed by dielectric unit cells insensitive to polarization is presented in this article. The proposed unit cell can be implemented in any azimuth orientation, simplifying the design and the implementation of the Fresnel subzones, which is an advantage over the previous 3-D-printed Fresnel-lens designs. The unit cell exhibits a T-shaped geometry capable of providing no change in relative permittivity under TE polarizations orthogonal to each other. The novel design of the unit cell also provides robustness under oblique incidence and frequency. These features allow the radial arrangement of the unit cells to configure the subzones of the Fresnel lens, ensuring the desired relative permittivity. Additionally, the geometry of the printed unit cells enables self-supported subzones with the minimum number of unit cells per subzone. A 3-D-printed prototype of the proposed Fresnel lens was manufactured by stereolithography (SLA). The measurement results showed a good agreement with the simulated ones. The measured gain was 26.5 ± 0.5 dBi from 55 GHz to 65 GHz with a mean antenna efficiency of 79%. Full article

(This article belongs to the Special Issue Metastructures and Antennas with Enhanced Properties for Modern Microwave and Millimeter-Wave Applications)

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12 pages, 788 KB

Open AccessArticle

On-Axis Resolution of a Circular Aperture

by Maria Antonia Maisto

Electronics 2021, 10(6), 729; https://doi.org/10.3390/electronics10060729 - 19 Mar 2021

Cited by 1 | Viewed by 3091

Abstract

In this paper, the problem to estimate the on-axis resolution in creating a desired field profile by radiation of an aperture A is addressed. The latter applies in both diffractive optics and antenna synthesis. This is because the ‘aperture theory’, A can schematize [...] Read more.

In this paper, the problem to estimate the on-axis resolution in creating a desired field profile by radiation of an aperture A is addressed. The latter applies in both diffractive optics and antenna synthesis. This is because the ‘aperture theory’, A can schematize a source, for example, an antenna or a lens illuminated by an incident field radiating a significant field only on the same aperture. The analysis refers to a customary axicon geometry consisting of a circle aperture transverse to the observation domain. The aim was to find a resolution formula allowing to highlight the impact of aperture geometrical parameters for configurations that are below the Fresnel approximation. The results show that the aperture cannot approximate the target field with the same level of accuracy along with the observation domain. In particular, near the aperture, smaller details can be retrieved and as the distance increases this ability degrades. Full article

(This article belongs to the Special Issue Photonic and Microwave Sensing Developments and Applications)

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15 pages, 3869 KB

Open AccessReview

Potential of Liquid-Crystal Materials for Millimeter-Wave Application

by Toshiaki Nose, Ryota Ito and Michinori Honma

Appl. Sci. 2018, 8(12), 2544; https://doi.org/10.3390/app8122544 - 8 Dec 2018

Cited by 17 | Viewed by 4920

Abstract

In this study, we reviewed three topics regarding the application of liquid-crystal (LC) materials to millimeter-wave (MMW) devices. It is essential to develop useful measurement methods for refractive indices of LC materials in the MMW region. Herein, a novel measurement method using optical [...] Read more.

In this study, we reviewed three topics regarding the application of liquid-crystal (LC) materials to millimeter-wave (MMW) devices. It is essential to develop useful measurement methods for refractive indices of LC materials in the MMW region. Herein, a novel measurement method using optical short is demonstrated using a Si semiconductor substrate. There are two approaches to develop MMW LC devices. One is the quasi-optical approach, which involves scaling up the optical components, and the other approach involves integrating the LC materials into high-frequency electric circuits. A three-dimensional (3D) printer is used to fabricate the Fresnel lens, which is a typical quasi-optical device useful in the MMW region, where we can develop the tunable lens by introducing LC materials. A planar-type MMW waveguide is advantageous for integrating the LC materials to develop LC MMW devices using the second approach. We investigated a useful microstrip-line-type LC phase shifter by developing a novel conversion circuit to introduce the LC material onto the dielectric substrate surface. A phase shifter is an important MMW component that is used to attain a phased array antenna system, and a minimal twin antenna array is demonstrated using the microstrip-line-type LC phase shifters. Full article

(This article belongs to the Special Issue Liquid Crystal THz Photonics: Materials, Devices and Applications)

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