Specially Designed Metamaterial Split Ring Resonator for High Resolution Imaging at Microwave Frequencies

Author(s):  
C. Bindu ◽  
Sreedevi P. Chakyar ◽  
Anju Sebastian ◽  
Jolly Andrews ◽  
V. P. Joseph
2012 ◽  
Vol 54 (6) ◽  
pp. 1415-1416 ◽  
Author(s):  
P. Menon. Ragi ◽  
K. S. Umadevi ◽  
Paul. Nees ◽  
Jovia Jose ◽  
M. V. Keerthy ◽  
...  

2016 ◽  
Vol 78 (10-3) ◽  
Author(s):  
Rammah A. Alahnomi ◽  
Z. Zakaria ◽  
E. Ruslan ◽  
Amyrul Azuan Mohd Bahar ◽  
Noor Azwan Shairi

A new sensor based on symmetrical split ring resonator (SSRR) functioning at microwave frequencies has been proposed in order to detect and characterize the properties of the materials. This sensor is based on perturbation theory, in which the dielectric properties of the material affect the quality factor and resonance frequency of the microwave resonator. Conventionally, coaxial cavity, waveguide, dielectric resonator techniques have been used for characterizing materials. However, these techniques are often large, and expensive to build, which restricts their use in many important applications. Thus, the proposed bio-sensing technique presents advantages such as high measurement sensitivity (around 400 Q-factor) with the capability of suppressing undesired harmonic spurious and permits potentially material characterization and determination.  Hence, using a specific experimental methodology, tests performed have demonstrated the biosensor ability to characterize at least four references materials with known permittivity (Air, Roger Duriod RT 5880, Roger Duriod RT 4530, FR4) and one material with unknown permittivity (Beef). Accordingly, the numerically established relations are experimentally verified for these reference materials and the results indicated that the average estimation error of measuring the permittivity was 2.56 % at resonant of around 2.2 GHz.  The proposed design is useful for various applications such as food industry, medicine, pharmacy, bio-sensing and quality control


2019 ◽  
Author(s):  
C. Bindu ◽  
Sreedevi P. Chakyar ◽  
Anju Sebastian ◽  
Sikha K. Simon ◽  
Jovia Jose ◽  
...  

2018 ◽  
Vol 96 (8) ◽  
pp. 878-886 ◽  
Author(s):  
J.S. Bobowski

A method is proposed to experimentally determine the effective complex permeability of split-ring resonator (SRR) arrays used in the design of metamaterials at microwave frequencies. We analyze the microwave response of a loop-gap resonator (LGR) whose bore has been partially loaded with one or more SRRs. Our analysis reveals that the resonance frequency, magnetic plasma frequency, and damping constant of the effective permeability of the SRR array can be extracted from fits to the reflection coefficient (S11) of an inductively coupled LGR. We propose LGR designs that would allow both a one-dimensional array of SRRs and small three-dimensional arrays of SRRs to be characterized. Finally, we demonstrate the method using a toroidal LGR loaded with a single extended SRR of length z.


Author(s):  
J.M. Cowley

By extrapolation of past experience, it would seem that the future of ultra-high resolution electron microscopy rests with the advances of electron optical engineering that are improving the instrumental stability of high voltage microscopes to achieve the theoretical resolutions of 1Å or better at 1MeV or higher energies. While these high voltage instruments will undoubtedly produce valuable results on chosen specimens, their general applicability has been questioned on the basis of the excessive radiation damage effects which may significantly modify the detailed structures of crystal defects within even the most radiation resistant materials in a period of a few seconds. Other considerations such as those of cost and convenience of use add to the inducement to consider seriously the possibilities for alternative approaches to the achievement of comparable resolutions.


Author(s):  
Max T. Otten ◽  
Wim M.J. Coene

High-resolution imaging with a LaB6 instrument is limited by the spatial and temporal coherence, with little contrast remaining beyond the point resolution. A Field Emission Gun (FEG) reduces the incidence angle by a factor 5 to 10 and the energy spread by 2 to 3. Since the incidence angle is the dominant limitation for LaB6 the FEG provides a major improvement in contrast transfer, reducing the information limit to roughly one half of the point resolution. The strong improvement, predicted from high-resolution theory, can be seen readily in diffractograms (Fig. 1) and high-resolution images (Fig. 2). Even if the information in the image is limited deliberately to the point resolution by using an objective aperture, the improved contrast transfer close to the point resolution (Fig. 1) is already worthwhile.


Author(s):  
Xiao Zhang

Electron holography has recently been available to modern electron microscopy labs with the development of field emission electron microscopes. The unique advantage of recording both amplitude and phase of the object wave makes electron holography a effective tool to study electron optical phase objects. The visibility of the phase shifts of the object wave makes it possible to directly image the distributions of an electric or a magnetic field at high resolution. This work presents preliminary results of first high resolution imaging of ferroelectric domain walls by electron holography in BaTiO3 and quantitative measurements of electrostatic field distribution across domain walls.


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