PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Large-aperture planar lens antennas with gradient refractive index

2013-12-31
(Press-News.org) Contact information: CUI TieJun
tjcui@seu.edu.cn
Science China Press
Large-aperture planar lens antennas with gradient refractive index It was recently shown that large-aperture lens antennas can be designed by using gradient-index (GRIN) metamaterials and that higher directivity and gain can be obtained than with traditional dielectric lens antennas. This provides an effective method to design high-performance lens antennas. A paper titled "Three-dimensional large-aperture lens antennas with gradient refractive index," published in SCIENCE CHINA Information Sciences, 2013, No. 12, investigates the principles and performance of GRIN lens antennas from the perspectives of design, fabrication, and experiment. Lens antennas have traditionally been of two different compositions: either the dielectric delay or the metal accelerating lens. These two lens types are designed to focus electromagnetic waves by means of special hyperbolic or ellipsoidal geometric configurations, which can incur many difficulties in design and fabrication. Classical lenses made of homogeneous dielectrics use curved surfaces to compensate for phase differences, while metamaterial lenses make use of gradients in refractive index to realize the required phase changes. GRIN lenses offer several advantages: (1) a simple flat GRIN lens can be used to focus the electromagnetic waves and hence is easier to design and realize; (2) the impedance of a GRIN lens is easy to match with air, and hence little reflection loss exists to affect the antenna's efficiency; and (3) a wide range of indices of refraction can be obtained using metamaterials, making possible GRIN lenses that are much thinner than traditional ones. In this work, three-dimensional GRIN lenses are fabricated using multilayer inhomogeneous drilling holes or square ring resonators, which possess the desirable characteristics of high gain, broad bandwidth, and dual polarization. Two impedance-matching layers are proposed for the two sides of the GRIN lens, yielding very low reflection coefficients. In addition, an intriguing development has recently emerged in GRIN metamaterials—GRIN metasurfaces. By employing an idea similar to the GRIN slab lens to generate the required phase distributions, a GRIN metasurface can also be used to manipulate wavefronts for high-gain antenna performance. ### This work was sponsored in part by the National Natural Science Foundation of China (grants 60990320, 60990321, 60990324, 61171024, 61171026, and 61138001), the National High-Tech R&D (863) Program (Nos. 2011AA010202 and 2012AA030402), and the 111 Project (No. 111-2-05).

See the article: ZHOU X Y, ZOU X Y, YANG Y, MA H F, CUI T J. Three-dimensional large-aperture lens antennas with gradient refractive index. SCIENCE CHINA Information Sciences, 2013, 56: 120410, doi:10.1007/s11432-013-5038-8.

http://info.scichina.com:8084/sciFe/EN/abstract/abstract512917.shtml

Science China Press Co., Ltd. (SCP) is a scientific journal publishing company of the Chinese Academy of Sciences (CAS). For 60 years, SCP takes its mission to present to the world the best achievements by Chinese scientists on various fields of natural sciences researches.


ELSE PRESS RELEASES FROM THIS DATE:

Cloud mystery solved: Global temperatures to rise at least 4°C by 2100

2013-12-31
Cloud mystery solved: Global temperatures to rise at least 4°C by 2100 Cloud impact on climate sensitivity unveiled

Finnish research team reveals how emotions are mapped in the body

2013-12-31
Finnish research team reveals how emotions are mapped in the body Researchers Aalto University have revealed how emotions are experienced in the body Researchers Aalto University have revealed how emotions are experienced in the body. Emotions adjust our ...

Competition in a rough neighborhood: Plant success in a desert environment

2013-12-31
Competition in a rough neighborhood: Plant success in a desert environment Water use efficiency and relative growth rate govern competitive interactions in desert winter annuals Many people think of deserts as inhospitable places devoid of life, but numerous plants ...

Loyola bioethics study finds medical students concerned about desensitization to dying patients

2013-12-31
Loyola bioethics study finds medical students concerned about desensitization to dying patients Loyola's Neiswanger Institute study finds medical students concerned about becoming insensitive when dealing with a dying patient MAYWOOD, Ill. – The imminent death ...

New studies give strong boost to binary-star formation theory

2013-12-31
New studies give strong boost to binary-star formation theory VLA observations support 1 competing explanation for how double stars are formed Using the new capabilities of the upgraded Karl G. Jansky Very Large Array (VLA), scientists have discovered previously-unseen ...

Final recommendations on lung cancer screening

2013-12-31
Final recommendations on lung cancer screening Embargoed news from Annals of Intenral Medicine Final word: Task Force says screen high-risk populations for lung cancer High-risk adults between the ages of 55 and 80 should receive annual lung cancer screening ...

Climate change spurs tropical mangroves to expand in the north

2013-12-31
Climate change spurs tropical mangroves to expand in the north As mangrove trees lose ground to deforestation and urban sprawl, one development seems to be giving them a boost: climate change. Fewer winter cold snaps have enabled them to conquer new territory around their northern ...

Mangroves expand north as Florida freezes decline

2013-12-31
Mangroves expand north as Florida freezes decline Mangrove forests have been expanding northward along the Atlantic coast of Florida for the last few decades not because of a general warming trend, but likely because cold snaps there are becoming a thing of the ...

With few hard frosts, tropical mangroves push north

2013-12-31
With few hard frosts, tropical mangroves push north N Florida coast transformed by extreme weather change, not overall warming COLLEGE PARK, MD – Cold-sensitive mangrove forests have expanded dramatically along Florida's Atlantic Coast as the frequency of killing frosts ...

Minority physicians care for a majority of underserved patients in the US

2013-12-31
Minority physicians care for a majority of underserved patients in the US Minority physicians also play a large role in the care of patients with poorer health, according to a new study in JAMA Internal Medicine CAMBRIDGE, Mass. – Black, Hispanic and Asian ...

LAST 30 PRESS RELEASES:

KAIST Develops Retinal Therapy to Restore Lost Vision​

Adipocyte-hepatocyte signaling mechanism uncovered in endoplasmic reticulum stress response

Mammals were adapting from life in the trees to living on the ground before dinosaur-killing asteroid

Low LDL cholesterol levels linked to reduced risk of dementia

Thickening of the eye’s retina associated with greater risk and severity of postoperative delirium in older patients

Almost one in ten people surveyed report having been harmed by the NHS in the last three years

Enhancing light control with complex frequency excitations

New research finds novel drug target for acute myeloid leukemia, bringing hope for cancer patients

New insight into factors associated with a common disease among dogs and humans

Illuminating single atoms for sustainable propylene production

New study finds Rocky Mountain snow contamination

Study examines lactation in critically ill patients

UVA Engineering Dean Jennifer West earns AIMBE’s 2025 Pierre Galletti Award

Doubling down on metasurfaces

New Cedars-Sinai study shows how specialized diet can improve gut disorders

Making moves and hitting the breaks: Owl journeys surprise researchers in western Montana

PKU Scientists simulate the origin and evolution of the North Atlantic Oscillation

ICRAFT breakthrough: Unlocking A20’s dual role in cancer immunotherapy

How VR technology is changing the game for Alzheimer’s disease

A borrowed bacterial gene allowed some marine diatoms to live on a seaweed diet

Balance between two competing nerve proteins deters symptoms of autism in mice

Use of antifungals in agriculture may increase resistance in an infectious yeast

Awareness grows of cancer risk from alcohol consumption, survey finds

The experts that can outsmart optical illusions

Pregnancy may reduce long COVID risk

Scientists uncover novel immune mechanism in wheat tandem kinase

Three University of Virginia Engineering faculty elected as AAAS Fellows

Unintentional drug overdoses take a toll across the U.S. unequally, study finds

A step toward plant-based gelatin

ECMWF unveils groundbreaking ML tool for enhanced fire prediction

[Press-News.org] Large-aperture planar lens antennas with gradient refractive index