scholarly journals Microwave Measurements of Electromagnetic Properties of Materials

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5097
Author(s):  
Jerzy Krupka
Keyword(s):  
Sheet Resistance ◽  
Transmission Lines ◽  
Complex Permittivity ◽  
Practical Interest ◽  
Measurement Methods ◽  
Electromagnetic Properties ◽  
Complex Permeability ◽  
Microwave Measurements ◽  
Microwave Frequencies ◽  
Properties Of Materials

A review of measurement methods of the basic electromagnetic parameters of materials at microwave frequencies is presented. Materials under study include dielectrics, semiconductors, conductors, superconductors, and ferrites. Measurement methods of the complex permittivity, the complex permeability tensor, and the complex conductivity and related parameters, such as resistivity, the sheet resistance, and the ferromagnetic linewidth are considered. For dielectrics and ferrites, the knowledge of their complex permittivity and the complex permeability at microwave frequencies is of practical interest. Microwave measurements allow contactless measurements of their resistivity, conductivity, and sheet resistance. These days contactless conductivity measurements have become more and more important, due to the progress in materials technology and the development of new materials intended for the electronic industry such as graphene, GaN, and SiC. Some of these materials, such as GaN and SiC are not measurable with the four-point probe technique, even if they are conducting. Measurement fixtures that are described in this paper include sections of transmission lines, resonance cavities, and dielectric resonators.

scholarly journals Complex permittivity, permeability and microwave absorbing properties of Co–Ti substituted strontium hexaferrite

2016 ◽  
Vol 34 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Sukhleen Bindra Narang ◽  
Pawandeep Kaur ◽  
Shalini Bahel
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Complex Permittivity ◽  
Effective Means ◽  
Strontium Ferrite ◽  
Electromagnetic Properties ◽  
Strontium Hexaferrite ◽  
Complex Permeability ◽  
Permeability Constant ◽  
Dielectric Constant And Loss

AbstractM-type strontium ferrite with compositions SrFe(12-2x)CoxTixO19 (x = 0.0, 0.3, 0.5, 0.7, 1.0), were prepared by two route ceramic method. The effects of Co–Ti substitution on their microstructure, electromagnetic properties, and microwave absorptive behavior were analyzed. The complex permittivity (∊′-j∊″) and complex permeability (μ′-jμ″) have been measured from 8.2 to 12.4 GHz using a network analyzer. Scanning electron microscope was used to analyze the grain size distribution and porosity of the ferrite. X-ray diffraction confirmed the M-type structure of the doped strontium ferrite. Vibrating sample magnetometer was used to study hysteresis loop of the ferrite. This study suggests that the control of grain size, decrease in coercivity and enhanced values of dielectric constant and loss are effective means to improve microwave absorption. The dielectric constant and loss were enhanced in comparison to the permeability constant and loss over the entire frequency range.

scholarly journals Effect of different permeability on electromagnetic properties of absorbing materials

2018 ◽  
Vol 197 ◽  
pp. 02015 ◽  
Author(s):  
Riser Fahdiran ◽  
Yuliyanti Dwi Utami ◽  
Erfan Handoko
Keyword(s):  
Transmission Line ◽  
Reflection Loss ◽  
Single Layer ◽  
Electromagnetic Properties ◽  
Complex Permeability ◽  
Transmission Line Theory ◽  
Microwave Frequencies ◽  
Microwave Absorbing Properties ◽  
Absorbing Materials ◽  
Line Theory

In this study, we have simulated and investigated electromagnetic properties of six types materials using a single layer metal backed absorber model that were determined at microwave frequencies 8.2 up to12.4 GHz. The reflection loss was simulated for different thicknesses in the range of 0.85 to 1.05 mm based on the relative complex permeability and permittivity referring to transmission line theory. The optimal microwave absorbing properties was be resulted by A3 sample. The minimum RL of −23.84 dB can be obtained at 10.72 GHz with thin thickness of 0.95 mm. This method paves a new avenue to design magnetic and dielectric absorbing materials.

Microwave Materials Permittivity and Permeability Measurement Methods

2020 ◽  
Vol 11 (11) ◽  
pp. 4-16
Author(s):  
Stanislav Yu. BOBROVSKIY ◽  
◽  
Andrey N. LAGAR’KOV ◽  
Konstantin N. ROZANOV ◽  
◽  
...  
Keyword(s):  
Transmission Lines ◽  
Measurement Errors ◽  
Coaxial Line ◽  
Measurement Methods ◽  
Permeability Measurement ◽  
Scalar Resonance ◽  
Permittivity And Permeability ◽  
Properties Of Materials ◽  
Microwave Materials ◽  
Microwave Permittivity

Methods for measuring the microwave permittivity and permeability of materials are considered. The specific features and applicability conditions of measurement methods in transmission lines and in free space are shown, and the measurement errors are analyzed along with the calibration procedures applied for reducing the errors. Individual sections of the articles contain descriptions of scalar, resonance, quasistatic, and quasioptic methods. It has been determined that out of many existing techniques, the NicolsonRossWeir measurement method in a coaxial line and also the method for measuring the permeability of thin ferromagnetic films with the use of a shortcircuited strip cell are most widely applied. By using these methods, the majority of matters concerned with studying the microwave properties of materials can be solved.

The Electromagnetic Properties of Materials Program at Nist

1992 ◽  
Vol 269 ◽  
Author(s):  
Claude M. Weil
Keyword(s):  
Magnetic Materials ◽  
Measurement Techniques ◽  
Electromagnetic Properties ◽  
Microwave Frequencies ◽  
Properties Of Materials

ABSTRACTThe Electromagnetic Properties of Materials (EPM) program at the National Institute of Standards and Technology (NIST) is described, including an outline of the current goals of the project as well as some details of measurement techniques being used at NIST for characterizing dielectric and magnetic materials at RF and microwave frequencies.

Applications of metamaterial sensors: a review

2021 ◽  
pp. 1-15
Author(s):  
Divya Prakash ◽  
Nisha Gupta
Keyword(s):  
Electromagnetic Interaction ◽  
High Sensitivity ◽  
Ring Resonators ◽  
Electromagnetic Properties ◽  
Physical Parameters ◽  
Split Ring ◽  
Split Ring Resonators ◽  
Quality Testing ◽  
Properties Of Materials ◽  
Metamaterial Absorbers

Abstract Sensors based on metamaterial absorbers are very promising when it comes to high sensitivity and quality factor, cost, and ease of fabrication. The absorbers could be used to sense physical parameters such as temperature, pressure, density as well as they could be used for determining electromagnetic properties of materials and their characterization. In this work, an attempt has been made to explore the various possible applications of these sensors. Metamaterial-based sensors are very popular for its diverse applications in areas such as biomedical, chemical industry, food quality testing, agriculture. Split-ring resonators with various shapes and topologies are the most frequently used structures where the sensing principle is based on electromagnetic interaction of the material under test with the resonator. Overcoming the design challenges using metamaterial sensors involving several constraints such as cost, compactness, reusability, ease in fabrication, and robustness is also addressed.

scholarly journals Microstructure and Electromagnetic Properties of Ni-Zn-Co Ferrite up to 20 GHz

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Charalampos Stergiou
Keyword(s):  
Wall Motion ◽  
Wave Attenuation ◽  
Domain Wall Motion ◽  
Electromagnetic Properties ◽  
Complex Permeability ◽  
Microwave Dielectric ◽  
Zn Ferrite ◽  
Spin Resonance ◽  
Production Stages

The present paper examines the relation between different developed microstructures and the microwave electromagnetic properties in Ni-Zn-Co ferrite. To this end, the Ni0.25Zn0.25Co0.5Fe2O4composition has been prepared with the conventional ceramic process with varied prefiringTP(750°C, 1000°C) and sinteringTStop temperatures (1200°C, 1250°C). When lower temperatures are applied in these production stages, incomplete microstructures with low density, higher porosity, or finer grains are achieved. On account of these features, the contributions of domain wall motion and spin rotation to the complex permeabilityμ⁎(f)move to higher frequencies, whereas microwave dielectric permittivityε⁎(f)is decreased. In particular in conjunction with the high Co content, the wall relaxation and spin resonance are interestingly forced to occur at 850 MHz and 8.05 GHz, respectively. Regarding the electromagnetic wave attenuation, the ferrite annealed at lower temperatures exhibits strong return loss peaks at higher frequencies, but without other performance improvement. We should notice that the variations in sintering temperatureTSyield the maximum changes in the recorded parameters, including the coercive field,μ⁎(f),andε⁎(f), indicating the inferior role of prefiringTPin Ni-Zn ferrite.

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