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Special Issue "Metamaterials for Near-Field Microwaves Sensing"

A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Sensor Materials".

Deadline for manuscript submissions: closed (31 March 2021).

Special Issue Editors

Prof. Dr. Omar M. Ramahi
E-Mail Website
Guest Editor
Electrical and Computer Engineering Department, University of Waterloo, Waterloo, ON N2L 3G1, Canada
Interests: radiating systems; theoretical and computational electromagnetics; electromagnetic compatibility; interference and electronic packaging; biomedical applications of electromagnetics; photonics; material measurements; antennas; microwaves & photonics; medical imaging; scanning; energy harvesting/bio-energy; renewable energy; sensors and devices
Special Issues and Collections in MDPI journals
Prof. Dr. Vahid Nayyeri
E-Mail Website
Guest Editor
School of Advanced Technology, Iran University of Science and Technology, Tehran, Iran
Interests: Material Characterization; Microwave Circuits; Artificial Intelligence
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

When Smith, Pendry, and others started tinkering with split-ring resonators (SRR) for realizing double negative media, little did we know that these earlier ground-breaking works would usher in the beginning of a completely different perspective on the design of all types of electromagnetics-based systems. The SRR, or any other resonator that has dimensions much smaller than its wavelength, were used as building blocks for metamaterials, which in turn can be designed to provide media with properties that cannot be found in nature.

While these exotic media enabled the cloaking and design of dispersion-controlled media, the applications were largely limited. One of the emerging applications for SRR or metamaterial particles in general is in the area of microwave sensing. In the years following Pendry’s seminal work, metamaterial particles were used for the characterization of the electromagnetic properties of media. These early applications demonstrated, arguably for the first time, the possibility of designing near-field sensors that are suitable for specific applications. In recent years, numerous papers have been published where metamaterial particles are used to sense a variety of physical quantities and even for highly sensitive detection.

This Special Issue is intended to provide a holistic perspective, as much as possible, on the concept of designing metamaterials or metamaterial particles for microwaves near-field sensing and detection. Contributions are encouraged from academics and industrialists whose work is related to this subject. Authors are specifically encouraged to be explicit in their narratives describing their philosophy and design procedure rather than focusing largely on results.

Prof. Dr. Omar M. Ramahi
Dr. Vahid Nayyeri
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Sensors is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Microwaves
  • Near-field sensing
  • Metamaterials
  • Split-ring resonators
  • Antennas
  • Material characterization
  • Surface detection
  • Sub-surface detection

Published Papers (4 papers)

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Research

Open AccessArticle
A Simple High-Resolution Near-Field Probe for Microwave Non-Destructive Test and Imaging
Sensors 2020, 20(9), 2670; https://doi.org/10.3390/s20092670 - 07 May 2020
Viewed by 737
Abstract
Non-destructive tests working at lower microwave frequencies have large advantages of dielectric material penetrability, lower equipment cost, and lower implementation complexity. However, the resolution will become worse as the work frequencies become lower. Relying on designing the structure of high field confinement, this [...] Read more.
Non-destructive tests working at lower microwave frequencies have large advantages of dielectric material penetrability, lower equipment cost, and lower implementation complexity. However, the resolution will become worse as the work frequencies become lower. Relying on designing the structure of high field confinement, this study realizes a simple complementary spiral resonators (CSRs)-based near-field probe for microwave non-destructive testing (NDT) and imaging around 390 MHz (λ = 769 mm) whereby very high resolution (λ/308, 2.5 mm) is achieved. By applying an ingenious structure where a short microstrip is connected to a microstrip ring to feed the CSR, the probe, that is a single-port microwave planar circuit, does not need any extra matching circuits, which has more application potential in sensor arraying compared with other microwave probes. The variation of the electric field distribution with the standoff distance (SOD) between the material under test and the probe are analyzed to reveal the operation mechanisms behind the improved sensitivity and resolution of the proposed probe. Besides, the detection abilities of the tiny defects in metal and non-metal materials are demonstrated by the related experiments. The smallest detectable crack and via in the non-metal materials and the metal materials are of a λ/1538 (0.5 mm) width, a λ/513 (1.5 mm) diameter, a λ/3846 (0.2 mm) width and a λ/513 (1.5 mm) diameter, respectively. Moreover, to further evaluate the performance of the proposed probe, the defects under skin layer in the multilayer composite materials and the defects under corrosion in the carbon steel are inspected and imaged. Due to lower work frequency, high resolution, outstanding detection abilities of tiny defects, and large potentials in sensor arraying, the proposed probe would be a good candidate for microwave NDT and imaging. Full article
(This article belongs to the Special Issue Metamaterials for Near-Field Microwaves Sensing)
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Open AccessArticle
Feasibility Study of Enhancing Microwave Brain Imaging Using Metamaterials
Sensors 2019, 19(24), 5472; https://doi.org/10.3390/s19245472 - 12 Dec 2019
Cited by 4 | Viewed by 1280
Abstract
We present an approach to enhance microwave brain imaging with an innovative metamaterial (MM) planar design based on a cross-shaped split-ring resonator (SRR-CS). The proposed metasurface is incorporated in different setups, and its interaction with EM waves is studied both experimentally and by [...] Read more.
We present an approach to enhance microwave brain imaging with an innovative metamaterial (MM) planar design based on a cross-shaped split-ring resonator (SRR-CS). The proposed metasurface is incorporated in different setups, and its interaction with EM waves is studied both experimentally and by using CST Microwave Studio® and is compared to a “no MM” case scenario. We show that the MM can enhance the penetration of the transmitted signals into the human head when placed in contact with skin tissue, acting as an impedance-matching layer. In addition, we show that the MM can improve the transceivers’ ability to detect useful “weak” signals when incorporated in a headband scanner for brain imaging by increasing the signal difference from a blood-like dielectric target introduced into the brain volume. Our results suggest that the proposed MM film can be a powerful hardware advance towards the development of scanners for brain haemorrhage detection and monitoring. Full article
(This article belongs to the Special Issue Metamaterials for Near-Field Microwaves Sensing)
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Open AccessArticle
Intelligent Sensing Using Multiple Sensors for Material Characterization
Sensors 2019, 19(21), 4766; https://doi.org/10.3390/s19214766 - 02 Nov 2019
Cited by 2 | Viewed by 1115
Abstract
This paper presents a concept of an intelligent sensing technique based on modulating the frequency responses of microwave near-field sensors to characterize material parameters. The concept is based on the assumption that the physical parameters being extracted such as fluid concentration are constant [...] Read more.
This paper presents a concept of an intelligent sensing technique based on modulating the frequency responses of microwave near-field sensors to characterize material parameters. The concept is based on the assumption that the physical parameters being extracted such as fluid concentration are constant over the range of frequency of the sensor. The modulation of the frequency response is based on the interactions between the material under test and multiple sensors. The concept is based on observing the responses of the sensors over a frequency wideband as vectors of many dimensions. The dimensions are then considered as the features for a neural network. With small datasets, the neural networks can produce highly accurate and generalized models. The concept is demonstrated by designing a microwave sensing system based on a two-port microstrip line exciting three-identical planar resonators. For experimental validation, the sensor is used to detect the concentration of a fluid material composed of two pure fluids. Very high accuracy is achieved. Full article
(This article belongs to the Special Issue Metamaterials for Near-Field Microwaves Sensing)
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Open AccessArticle
Sub-Wavelength Focusing in Inhomogeneous Media with a Metasurface Near Field Plate
Sensors 2019, 19(20), 4534; https://doi.org/10.3390/s19204534 - 18 Oct 2019
Cited by 1 | Viewed by 780
Abstract
Overcoming the diffraction limit, which enables focusing much less than the wavelength, requires tailoring the evanescent spectrum of an aperture’s field distribution. We model and simulate a corrugated near field plate, which can generate a sub-wavelength focus in inhomogeneous background media. All reactive [...] Read more.
Overcoming the diffraction limit, which enables focusing much less than the wavelength, requires tailoring the evanescent spectrum of an aperture’s field distribution. We model and simulate a corrugated near field plate, which can generate a sub-wavelength focus in inhomogeneous background media. All reactive coupling, between the metasurface near field plate and the focusing domain and among the corrugations in the metasurface, is taken into consideration with the finite element method, which we solve in combination with a constraint to generate a desired focus. Various geometries for the near field plate are considered and we demonstrate that the proposed method can effectively create a deeply sub-wavelength focus within a layered medium having properties resembling brain tissue. Such a device could find use as a detector of biological signals or for hyperthermic treatment near the skin surface. Full article
(This article belongs to the Special Issue Metamaterials for Near-Field Microwaves Sensing)
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