scholarly journals Metamaterials subwavelength terahertz resonant cavities

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
M. Al-Rubaiee ◽  
A. H. Al-Janabi ◽  
S. C. Fleming ◽  
A. Argyros
Keyword(s):  
Resonance Frequency ◽  
Band Gap ◽  
Electromagnetic Waves ◽  
Wire Array ◽  
Terahertz Range ◽  
Optical Components ◽  
Resonant Cavities ◽  
Bulk Properties ◽  
Unit Cells ◽  
Microscopic Features

AbstractOne of the unique properties of metamaterials is the ability to manipulate electromagnetic waves at subwavelength scales, made possible by their structure on these scales. Here, rather than consider effective bulk properties, we consider the properties of microscopic features based on considering resonant unit cells. We used wire array metamaterials to form localized resonant cavities by changing the resonance frequency of one or more unit cells, surrounded by unchanged unit cells that do not support resonance for the propagating mode (i.e. forming a band gap). We validate our approach experimentally with electromagnetic waves in the terahertz range, demonstrating and characterizing subwavelength resonant cavities in this range. These resonant cavities can pave the way for ultra-compact subwavelength waveguides and other optical components.

A Design of EBG-PIFA for RFID Applications in UHF Band

2013 ◽  
Vol 427-429 ◽  
pp. 1141-1144
Author(s):  
Hong Mei Li ◽  
Jin Yue Wang ◽  
Li Kun Xing ◽  
Xin Yu Cao ◽  
Tie Xin Yang
Keyword(s):  
Theoretical Prediction ◽  
Resonance Frequency ◽  
Band Gap ◽  
Radiation Patterns ◽  
Electromagnetic Band Gap ◽  
Unit Cells ◽  
Simulation And Experiment ◽  
Capacitor Structure ◽  
Rfid Applications ◽  
Uhf Band

One of the longstanding problems in planar inverted F antenna (PIFA) is its efficiency, which reduces as PIFA is placed too close to the ground. In this paper a kind of mushroom-like Electromagnetic band gap (EBG) structure with three conductor layers is designed In the UHF band, which has smaller unit cells and thinner thickness compared to classical ones. This kind of mushroom-like EBG structure is used as the reflector of PIFA with capacitor structure. It is demonstrated that PIFAs with EBG grounds have higher radiation efficiency than those with PEC ground. At the same time, no significant changes in the antenna resonance frequency and the radiation patterns are found. The theoretical prediction is well verified by results of both simulation and experiment.

scholarly journals Hypersensitized Metamaterials Based on a Corona-Shaped Resonator for Efficient Detection of Glucose

2020 ◽  
Vol 11 (1) ◽  
pp. 103
Author(s):  
Yadgar I. Abdulkarim ◽  
Fahmi F. Muhammadsharif ◽  
Mehmet Bakır ◽  
Halgurd N. Awl ◽  
Muharrem Karaaslan ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Glucose Concentration ◽  
Electromagnetic Waves ◽  
Surface Current ◽  
Superior Performance ◽  
Promising Candidate ◽  
Efficient Detection ◽  
Circular Structure ◽  
Clear Shift ◽  
Current Electric Field

In this work, a new design for a real-time noninvasive metamaterial sensor, based on a corona-shaped resonator, is proposed. The sensor was designed numerically and fabricated experimentally in order to be utilized for efficient detection of glucose in aqueous solutions such as water and blood. The sensor was inspired by a corona in-plane-shaped design with the presumption that its circular structure might produce a broader interaction of the electromagnetic waves with the glucose samples. A clear shift in the resonance frequency was observed for various glucose samples, which implies that the proposed sensor has a good sensitivity and can be easily utilized to distinguish any glucose concentration, even though their dielectric coefficients are close. Results showed a superior performance in terms of resonance frequency shift (1.51 GHz) and quality factor (246) compared to those reported in the literature. The transmission variation level ∆|S21| was investigated for glucose concentration in both water and blood. The sensing mechanism was elaborated through the surface current, electric field and magnetic field distributions on the corona resonator. The proposed metamaterials sensor is considered to be a promising candidate for biosensor and medicine applications in human glycaemia monitoring.

NONRECIPROCAL ELECTROMAGNETIC DEVICES IN GYROMAGNETIC PHOTONIC CRYSTALS

2013 ◽  
Vol 28 (02) ◽  
pp. 1441010 ◽  
Author(s):  
ZHI-YUAN LI ◽  
RONG-JUAN LIU ◽  
LIN GAN ◽  
JIN-XIN FU ◽  
JIN LIAN
Keyword(s):  
Magnetic Field ◽  
Band Gap ◽  
Electromagnetic Waves ◽  
Experimental Studies ◽  
Magnetic Surface ◽  
Electromagnetic Properties ◽  
Edge States ◽  
Bragg Scattering ◽  
Electromagnetic Devices ◽  
Gap Opening

Gyromagnetic photonic crystal (GPC) offers a promising way to realize robust transport of electromagnetic waves against backscattering from various disorders, perturbations and obstacles due to existence of unique topological electromagnetic states. The dc magnetic field exerting upon the GPC brings about the time-reversal symmetry breaking, splits the band degeneracy and opens band gaps where the topological chiral edge states (CESs) arise. The band gap can originate either from long-range Bragg-scattering effect or from short-range localized magnetic surface plasmon resonance (MSP). These topological edge states can be explored to construct backscattering-immune one-way waveguide and other nonreciprocal electromagnetic devices. In this paper we review our recent theoretical and experimental studies of the unique electromagnetic properties of nonreciprocal devices built in GPCs. We will discuss various basic issues like experimental instrumental setup, sample preparations, numerical simulation methods, tunable properties against magnetic field, band degeneracy breaking and band gap opening and creation of topological CESs. We will investigate the unidirectional transport properties of one-way waveguide under the influence of waveguide geometries, interface morphologies, intruding obstacles, impedance mismatch, lattice disorders, and material dissipation loss. We will discuss the unique coupling properties between one-wave waveguide and resonant cavities and their application as novel one-way bandstop filter and one-way channel-drop filter. We will also compare the CESs created in the Bragg-scattering band gap and the MSP band gap under the influence of lattice disorders. These results can be helpful for designing and exploring novel nonreciprocal electromagnetic devices for optical integration and information processing.

scholarly journals Treatment outcomes in patients with multiple and concomitant trauma managed with minimally invasive osteosynthesis technologies and electromagnetic waves of the terahertz range

2021 ◽  
Vol 27 (1) ◽  
pp. 6-12
Author(s):  
S.Yu. Lukin ◽  
◽  
Yu.P. Soldatov ◽  
A.N. Diachkov ◽  
◽  
...  
Keyword(s):  
Immune System ◽  
Minimally Invasive ◽  
Electromagnetic Waves ◽  
Bone Fractures ◽  
Damage Control ◽  
Medullary Canal ◽  
Terahertz Range ◽  
Control Group ◽  
Minimally Invasive Osteosynthesis ◽  
Group I

Purpose To assess the effectiveness of minimally invasive technologies of osteosynthesis and electromagnetic waves of the terahertz range in patients with multiple and concomitant trauma. Materials and methods The process of rehabilitation was studied in 513 patients with polytrauma of varying severity which was more than 26 points on the ISS scale. The patients were diagnosed with 545 injuries of different organs and systems. All patients with severe concomitant and multiple trauma were divided into 3 groups: Group I of controls, treated in1995–2001, consisted of 269 patients whose treatment was conservative and aggressive (surgical, with the use of plating or intramedullary osteosynthesis); Group II was the experimental study group consisting of subgroup A of 202 patients treated in 2002–2009 in whom “damage control” concept was applied and subgroup B of 42 patients treated in 2010–2017 using the damage control tactics and new minimally invasive methods of treatment and devices (non-invasive lung ventilation in intensive care for fat embolism; rational osteosynthesis in closed chest trauma; minimally invasive guided method of transosseous osteosynthesis, including the use of fixators with hydroxyapatite coating; rational surgical approach to pelvic bones; universal guide for reaming the medullary canal) and exposure to electromagnetic waves of the terahertz range (EMWTHR)of the xiphoid process of the sternum to stimulate the immune system. Results It was revealed that the use of minimally invasive, low-traumatic methods of treating bone fractures in severe polytrauma and methods stimulating the immune system and tissue regeneration (subgroup II B) contributed to an improvement of anatomical and functional results of treatment by 1.3 times compared with the control group. The quality of life of patients in this group, in comparison with the control group, was 1.6 times higher for injuries of the upper limb and 1.9 times higher for injuries of the lower limb. An integral analysis of the effectiveness of the treatment revealed a reliable increase in the effectiveness to a satisfactory level. Conclusion The use of EMWTHR in the complex treatment of such patients is a promising method for stimulating hematological and immunological processes. The first results described in the literature are optimistic.

scholarly journals Efficient and Compact Near-Field Coupled Hybrid Antenna Using a Single Radiating Subwavelength Split-Ring Resonator

Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 527
Author(s):  
Zinching Dang ◽  
Marco Rahm
Keyword(s):  
Resonance Frequency ◽  
Electromagnetic Waves ◽  
Ring Resonator ◽  
Near Field ◽  
Low Frequency ◽  
Split Ring Resonator ◽  
Dipole Antenna ◽  
Angular Width ◽  
Split Ring ◽  
Broadband Internet

Modern applications in the realms of wireless communication and mobile broadband Internet increase the demand for compact antennas with well defined directivity. Here, we present an approach for the design and implementation of hybrid antennas consisting of a classic feeding antenna that is near-field-coupled to a subwavelength resonator. In such a combined structure, the composite antenna always radiates at the resonance frequency of the subwavelength oscillator as well as at the resonance frequency of the feeding antenna. While the classic antenna serves as impedance-matched feeding element, the subwavelength resonator induces an additional resonance to the composite antenna. In general, these near-field coupled structures are known for decades and are lately published as near-field resonant parasitic antennas. We describe an antenna design consisting of a high-frequency electric dipole antenna at f d = 25 GHz that couples to a low-frequency subwavelength split-ring resonator, which emits electromagnetic waves at f SRR = 10.41 GHz. The radiating part of the antenna has a size of approximately 3.2 mm × 8 mm × 1 mm and thus is electrically small at this frequency with a product k · a = 0.5 . The input return loss of the antenna was moderate at − 18 dB and it radiated at a spectral bandwidth of 120 MHz. The measured main lobe of the antenna was observed at 60 ∘ with a − 3 dB angular width of 65 ∘ in the E-plane and at 130 ∘ with a − 3 dB angular width of 145 ∘ in the H-plane.

Square-shaped metal screens in the infrared to terahertz spectral region: Resonance frequency, band gap, and bandpass filter characteristics

2008 ◽  
Vol 104 (2) ◽  
pp. 023103 ◽  
Author(s):  
O. Sternberg ◽  
K. P. Stewart ◽  
Y. Hor ◽  
A. Bandyopadhyay ◽  
J. F. Federici ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Band Gap ◽  
Frequency Band ◽  
Spectral Region ◽  
Bandpass Filter

scholarly journals Evaluation of uncertainty effects to band gap behavior of circuitry-integrated piezoelectric metamaterial using order-reduced analysis

2018 ◽  
Vol 29 (12) ◽  
pp. 2677-2692 ◽  
Author(s):  
Wangbai Pan ◽  
Guoan Tang ◽  
Jiong Tang
Keyword(s):  
Band Gap ◽  
Parameter Uncertainty ◽  
Good Accuracy ◽  
Integrated System ◽  
Acoustic Metamaterials ◽  
Type Analysis ◽  
Design And Synthesis ◽  
Unit Cells ◽  
Geometry Configuration ◽  
Reduced Modeling

Acoustic metamaterials with unit cells that are integrated with piezoelectric transducer circuitry exhibit interesting band gap behaviors that can be used for wave/vibration manipulation. This research reports the evaluation of uncertainty effects to a typical piezoelectric metamaterial, where uncertainties in geometry/configuration and in circuitry elements are taken into consideration. Monte Carlo–type analysis is performed to assess the band gap features under these uncertainties. In order to facilitate tractable computation in uncertainty analysis, order-reduced modeling of the electro-mechanically integrated system is formulated. The component mode synthesis–based order-reduced modeling increases the computational efficiency significantly while maintaining good accuracy. Results show that the band gap behavior is generally less sensitive to configuration uncertainty but can be greatly affected by circuitry parameter uncertainty. These results can be used to guide the design and synthesis of piezoelectric metamaterials, and the method developed can be applied to the uncertainty quantification of other types of metamaterials.

Circularly Polarized Microstrip Antenna Using SLPD Electromagnetic Band Gap Structure

Frequenz ◽  
2020 ◽  
Vol 74 (1-2) ◽  
pp. 41-51
Author(s):  
Alka Verma ◽  
Anil Kumar Singh ◽  
Neelam Srivastava ◽  
Binod Kumar Kanaujia
Keyword(s):  
Band Gap ◽  
Microstrip Antenna ◽  
Impedance Bandwidth ◽  
Electromagnetic Band Gap ◽  
Circularly Polarized ◽  
Unit Cells ◽  
Measured Impedance ◽  
Band Gap Structure ◽  
Peak Gain ◽  
Gap Structure

AbstractIn this article, a new structure comprising of a novel compact slot loaded polarization dependent Electromagnetic Band Gap structure (SLPDEBG), which enhances the performance of circularly polarized rotated square patch antenna by placing SLPDEBG unit cells around it, has been designed. The proposed antenna, having dimensions 0.640 λo x 0.640 λ x 0.0128 λo (λo stands for the free space wavelength at 2.39 GHz), shows that the measured impedance bandwidth and AR bandwidth is 120 MHz and 50 MHz, respectively, with a peak gain of 3.52 dB. Some prominent features of the proposed structure are: front to back ratio of 64, 3 db, beamwidth of 92° at xz-plane and 74° at yz-plane. This prototype antenna finds its application in wireless communication of ISM band. Good performance of the proposed antenna is verified by the close agreement between the simulated and measured results.

Selective Transmission of Electromagnetic Wave by Using Diamond Photonic Crystals with Graded Lattice Spacing

2006 ◽  
Vol 45 ◽  
pp. 1139-1144
Author(s):  
Soshu Kirihara ◽  
Yoshinari Miyamoto
Keyword(s):  
Photonic Crystals ◽  
Band Gap ◽  
Electromagnetic Waves ◽  
Lattice Spacing ◽  
Three Dimensional ◽  
Dielectric Constants ◽  
Microwave Antenna ◽  
Diamond Structure ◽  
Band Calculation ◽  
Graded Lattice

Three-dimensional electromagnetic or photonic crystals with periodic variations of the dielectric constants were fabricated by using a rapid prototyping method called stereolithography. Millimeter-order epoxy lattices with a diamond structure were designed to reflect electromagnetic waves by forming an electromagnetic band gap in GHz range. Titania based ceramic particles were dispersed into the lattice to control the dielectric constant. The diamond lattice structures formed the perfect band gap reflecting electromagnetic waves for all directions. The location of the band gap agreed with the band calculation using the plane wave propagation method. The diamond structures with graded lattice spacing were successfully fabricated as well, resulting in the directional transmission of microwaves. The stretching ratio of the lattice spacing in the crystal structure was changed according to the electromagnetic band calculation. A microwave antenna head composed of the diamond structure with graded lattice spacing was fabricated which achieved the unidirectional transmission.

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