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Special Issue "Metamaterial-Inspired Sensors"

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

Deadline for manuscript submissions: closed (31 January 2015)

Special Issue Editor

Guest Editor
Prof. Dr. Omar M. Ramahi

Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario N2L3G1, Canada
Website | E-Mail
Phone: 1-519-888-4567
Interests: sensors; energy harvesting; advanced electromagnetic applications; metamaterials

Special Issue Information

Dear Colleagues,

The theoretical musings of Veselago almost half a century ago on what would happen if negative permeability and permittivity were practically realized affected the field of sensors in a most unexpected way. Based on the metamaterial that realized Veselago's dreams, inexpensive and highly sensitive sensors became a reality. Metamaterials are made from an ensemble of electrically-small particles. Each of these particles is essentially a resonator. Since the particles are electrically-small, their individual frequency bandwidth is astoundingly small too. This feature makes these particles notoriously unattractive for antenna applications but highly attractive for sensing applications.

This special issue is dedicated to metamaterial-based sensors, in particular, and electrically-small resonators in general. We envision this special issue to include high-quality original papers or comprehensive tutorial papers with focus on any of the following themes:

1. Establishing a more formal approach to characterization of electrically-small resonators for sensing applications.
2. Highlighting the importance of advanced material engineering producing low-loss substrates and their impact on sensing.
3. Highlighting trade off in sensor development between frequency, fabrication complexity, cost, size, etc.
4. Distributed or multi-sensor applications.
5. Chemical, biological or material sensing.
6. Intelligent sensing.
7. Electrically-small sensors spanning the electromagnetic spectrum from DC to light.

Prof. Dr. Omar M. Ramahi
Guest Editor

Submission

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. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as 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 refereed through a 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 monthly 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 1800 CHF (Swiss Francs).


Keywords

  • sensors
  • metamaterials
  • microwaves
  • electromagnetic fields
  • non-invasive detection
  • sub-surface detection

Published Papers (8 papers)

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Research

Open AccessArticle A Negative Index Metamaterial-Inspired UWB Antenna with an Integration of Complementary SRR and CLS Unit Cells for Microwave Imaging Sensor Applications
Sensors 2015, 15(5), 11601-11627; doi:10.3390/s150511601
Received: 21 February 2015 / Accepted: 30 April 2015 / Published: 20 May 2015
Cited by 9 | PDF Full-text (5237 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a negative index metamaterial incorporated UWB antenna with an integration of complementary SRR (split-ring resonator) and CLS (capacitive loaded strip) unit cells for microwave imaging sensor applications. This metamaterial UWB antenna sensor consists of four unit cells along one axis,
[...] Read more.
This paper presents a negative index metamaterial incorporated UWB antenna with an integration of complementary SRR (split-ring resonator) and CLS (capacitive loaded strip) unit cells for microwave imaging sensor applications. This metamaterial UWB antenna sensor consists of four unit cells along one axis, where each unit cell incorporates a complementary SRR and CLS pair. This integration enables a design layout that allows both a negative value of permittivity and a negative value of permeability simultaneous, resulting in a durable negative index to enhance the antenna sensor performance for microwave imaging sensor applications. The proposed MTM antenna sensor was designed and fabricated on an FR4 substrate having a thickness of 1.6 mm and a dielectric constant of 4.6. The electrical dimensions of this antenna sensor are 0.20 λ × 0.29 λ at a lower frequency of 3.1 GHz. This antenna sensor achieves a 131.5% bandwidth (VSWR < 2) covering the frequency bands from 3.1 GHz to more than 15 GHz with a maximum gain of 6.57 dBi. High fidelity factor and gain, smooth surface-current distribution and nearly omni-directional radiation patterns with low cross-polarization confirm that the proposed negative index UWB antenna is a promising entrant in the field of microwave imaging sensors. Full article
(This article belongs to the Special Issue Metamaterial-Inspired Sensors)
Open AccessArticle Intelligent Detection of Cracks in Metallic Surfaces Using a Waveguide Sensor Loaded with Metamaterial Elements
Sensors 2015, 15(5), 11402-11416; doi:10.3390/s150511402
Received: 28 January 2015 / Revised: 5 May 2015 / Accepted: 6 May 2015 / Published: 15 May 2015
Cited by 4 | PDF Full-text (468 KB) | HTML Full-text | XML Full-text
Abstract
This work presents a real life experiment of implementing an artificial intelligence model for detecting sub-millimeter cracks in metallic surfaces on a dataset obtained from a waveguide sensor loaded with metamaterial elements. Crack detection using microwave sensors is typically based on human observation
[...] Read more.
This work presents a real life experiment of implementing an artificial intelligence model for detecting sub-millimeter cracks in metallic surfaces on a dataset obtained from a waveguide sensor loaded with metamaterial elements. Crack detection using microwave sensors is typically based on human observation of change in the sensor’s signal (pattern) depicted on a high-resolution screen of the test equipment. However, as demonstrated in this work, implementing artificial intelligence to classify cracked from non-cracked surfaces has appreciable impact in terms of sensing sensitivity, cost, and automation. Furthermore, applying artificial intelligence for post-processing data collected from microwave sensors is a cornerstone for handheld test equipment that can outperform rack equipment with large screens and sophisticated plotting features. The proposed method was tested on a metallic plate with different cracks and the obtained experimental results showed good crack classification accuracy rates. Full article
(This article belongs to the Special Issue Metamaterial-Inspired Sensors)
Open AccessArticle Angular Displacement and Velocity Sensors Based on Coplanar Waveguides (CPWs) Loaded with S-Shaped Split Ring Resonators (S-SRR)
Sensors 2015, 15(5), 9628-9650; doi:10.3390/s150509628
Received: 23 March 2015 / Revised: 14 April 2015 / Accepted: 21 April 2015 / Published: 23 April 2015
Cited by 8 | PDF Full-text (2142 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, angular displacement and angular velocity sensors based on coplanar waveguide (CPW) transmission lines and S-shaped split ring resonators (S-SRRs) are presented. The sensor consists of two parts, namely a CPW and an S-SRR, both lying on parallel planes. By this
[...] Read more.
In this paper, angular displacement and angular velocity sensors based on coplanar waveguide (CPW) transmission lines and S-shaped split ring resonators (S-SRRs) are presented. The sensor consists of two parts, namely a CPW and an S-SRR, both lying on parallel planes. By this means, line-to-resonator magnetic coupling arises, the coupling level being dependent on the line-to-resonator relative angular orientation. The line-to-resonator coupling level is the key parameter responsible for modulating the amplitude of the frequency response seen between the CPW ports in the vicinity of the S-SRR fundamental resonance frequency. Specifically, an amplitude notch that can be visualized in the transmission coefficient is changed by the coupling strength, and it is characterized as the sensing variable. Thus, the relative angular orientation between the two parts is measured, when the S-SRR is attached to a rotating object. It follows that the rotation angle and speed can be inferred either by measuring the frequency response of the S-SRR-loaded line, or the response amplitude at a fixed frequency in the vicinity of resonance. It is in addition shown that the angular velocity can be accurately determined from the time-domain response of a carrier time-harmonic signal tuned at the S-SRR resonance frequency. The main advantage of the proposed device is its small size directly related to the small electrical size of the S-SRR, which allows for the design of compact angular displacement and velocity sensors at low frequencies. Despite the small size of the fabricated proof-of-concept prototype (electrically small structures do not usually reject signals efficiently), it exhibits good linearity (on a logarithmic scale), sensitivity and dynamic range. Full article
(This article belongs to the Special Issue Metamaterial-Inspired Sensors)
Open AccessArticle Sensing Based on Fano-Type Resonance Response of All-Dielectric Metamaterials
Sensors 2015, 15(4), 9344-9359; doi:10.3390/s150409344
Received: 31 January 2015 / Revised: 17 March 2015 / Accepted: 15 April 2015 / Published: 21 April 2015
Cited by 2 | PDF Full-text (2828 KB) | HTML Full-text | XML Full-text
Abstract
A new sensing approach utilizing Mie resonances in metamaterial arrays composed of dielectric resonators is proposed. These arrays were found to exhibit specific, extremely high-Q factor (up to 15,000) resonances at frequencies corresponding to the lower edge of the array second transmission band.
[...] Read more.
A new sensing approach utilizing Mie resonances in metamaterial arrays composed of dielectric resonators is proposed. These arrays were found to exhibit specific, extremely high-Q factor (up to 15,000) resonances at frequencies corresponding to the lower edge of the array second transmission band. The observed resonances possessed with features typical for Fano resonances (FRs), which were initially revealed in atomic processes and recently detected in macro-structures, where they resulted from interference between local resonances and a continuum of background waves. Our studies demonstrate that frequencies and strength of Fano-type resonances in all-dielectric arrays are defined by interaction between local Mie resonances and Fabry-Perot oscillations of Bloch eigenmodes that makes possible controlling the resonance responses by changing array arrangements. The opportunity for obtaining high-Q responses in compact arrays is investigated and promising designs for sensing the dielectric properties of analytes in the ambient are proposed. Full article
(This article belongs to the Special Issue Metamaterial-Inspired Sensors)
Figures

Open AccessArticle Dielectric Sensors Based on Electromagnetic Energy Tunneling
Sensors 2015, 15(4), 7844-7856; doi:10.3390/s150407844
Received: 10 February 2015 / Revised: 12 March 2015 / Accepted: 24 March 2015 / Published: 31 March 2015
Cited by 1 | PDF Full-text (644 KB) | HTML Full-text | XML Full-text
Abstract
We show that metallic wires embedded in narrow waveguide bends and channels demonstrate resonance behavior at specific frequencies. The electromagnetic energy at these resonances tunnels through the narrow waveguide channels with almost no propagation losses. Under the tunneling behavior, high-intensity electromagnetic fields are
[...] Read more.
We show that metallic wires embedded in narrow waveguide bends and channels demonstrate resonance behavior at specific frequencies. The electromagnetic energy at these resonances tunnels through the narrow waveguide channels with almost no propagation losses. Under the tunneling behavior, high-intensity electromagnetic fields are produced in the vicinity of the metallic wires. These intense field resonances can be exploited to build highly sensitive dielectric sensors. The sensor operation is explained with the help of full-wave simulations. A practical setup consisting of a 3D waveguide bend is presented to experimentally observe the tunneling phenomenon. The tunneling frequency is predicted by determining the input impedance minima through a variational formula based on the Green function of a probe-excited parallel plate waveguide. Full article
(This article belongs to the Special Issue Metamaterial-Inspired Sensors)
Open AccessArticle A Naked Eye Refractive Index Sensor with a Visible Multiple Peak Metamaterial Absorber
Sensors 2015, 15(4), 7454-7461; doi:10.3390/s150407454
Received: 18 November 2014 / Revised: 11 March 2015 / Accepted: 19 March 2015 / Published: 26 March 2015
Cited by 3 | PDF Full-text (2929 KB) | HTML Full-text | XML Full-text
Abstract
We report a naked eye refractive index sensor with a visible metamaterial absorber. The visible metamaterial absorber consisting of a silver dendritic/dielectric/metal structure shows multiple absorption peaks. By incorporating a gain material (rhodamine B) into the dielectric layer, the maximal magnitude of the
[...] Read more.
We report a naked eye refractive index sensor with a visible metamaterial absorber. The visible metamaterial absorber consisting of a silver dendritic/dielectric/metal structure shows multiple absorption peaks. By incorporating a gain material (rhodamine B) into the dielectric layer, the maximal magnitude of the absorption peak can be improved by about 30%. As the metamaterial absorber is sensitive to the refractive index of glucose solutions, it can function as a sensor that quickly responds to variations of the refractive index of the liquid. Meanwhile, since the response is presented via color changes, it can be clearly observed by the naked eyes. Further experiments have confirmed that the sensor can be used repeatedly. Full article
(This article belongs to the Special Issue Metamaterial-Inspired Sensors)
Figures

Open AccessArticle Wireless Measurement of Elastic and Plastic Deformation by a Metamaterial-Based Sensor
Sensors 2014, 14(10), 19609-19621; doi:10.3390/s141019609
Received: 14 August 2014 / Revised: 30 September 2014 / Accepted: 14 October 2014 / Published: 20 October 2014
Cited by 5 | PDF Full-text (1785 KB) | HTML Full-text | XML Full-text
Abstract
We report remote strain and displacement measurement during elastic and plastic deformation using a metamaterial-based wireless and passive sensor. The sensor is made of a comb-like nested split ring resonator (NSRR) probe operating in the near-field of an antenna, which functions as both
[...] Read more.
We report remote strain and displacement measurement during elastic and plastic deformation using a metamaterial-based wireless and passive sensor. The sensor is made of a comb-like nested split ring resonator (NSRR) probe operating in the near-field of an antenna, which functions as both the transmitter and the receiver. The NSRR probe is fixed on a standard steel reinforcing bar (rebar), and its frequency response is monitored telemetrically by a network analyzer connected to the antenna across the whole stress-strain curve. This wireless measurement includes both the elastic and plastic region deformation together for the first time, where wired technologies, like strain gauges, typically fail to capture. The experiments are further repeated in the presence of a concrete block between the antenna and the probe, and it is shown that the sensing system is capable of functioning through the concrete. The comparison of the wireless sensor measurement with those undertaken using strain gauges and extensometers reveals that the sensor is able to measure both the average strain and the relative displacement on the rebar as a result of the applied force in a considerably accurate way. The performance of the sensor is tested for different types of misalignments that can possibly occur due to the acting force. These results indicate that the metamaterial-based sensor holds great promise for its accurate, robust and wireless measurement of the elastic and plastic deformation of a rebar, providing beneficial information for remote structural health monitoring and post-earthquake damage assessment. Full article
(This article belongs to the Special Issue Metamaterial-Inspired Sensors)
Figures

Open AccessArticle Metallic Strip Gratings in the Sub-Subwavelength Regime
Sensors 2014, 14(7), 11786-11804; doi:10.3390/s140711786
Received: 16 May 2014 / Revised: 18 June 2014 / Accepted: 25 June 2014 / Published: 4 July 2014
Cited by 5 | PDF Full-text (2599 KB) | HTML Full-text | XML Full-text
Abstract
Metallic strip gratings (MSG) have different applications, ranging from printed circuits to filters in microwave domains. When they are under the influence of an electromagnetic field, evanescent and/or abnormal modes appear in the region between the traces, their utilization leading to the development
[...] Read more.
Metallic strip gratings (MSG) have different applications, ranging from printed circuits to filters in microwave domains. When they are under the influence of an electromagnetic field, evanescent and/or abnormal modes appear in the region between the traces, their utilization leading to the development of new electromagnetic nondestructive evaluation methods. This paper studies the behavior of MSGs in the sub-subwavelength regime when they are excited with TEz or TMz polarized plane waves and the slits are filled with different dielectrics. The appearance of propagating, evanescent and abnormal modes is emphasized using an electromagnetic sensor with metamaterials lens realized with two conical Swiss rolls, which allows the extraction of the information carried by the guided evanescent waves. The evanescent waves, manipulated by the electromagnetic sensor with metamaterial lenses, improve the electromagnetic images so that a better spatial resolution is obtained, exceeding the limit imposed by diffraction. Their theoretical and experimental confirmation opens the perspective for development of new types of sensors working in radio and microwave frequencies. Full article
(This article belongs to the Special Issue Metamaterial-Inspired Sensors)

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

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