High loss liquid dielectric characterization: Comparison of microwave waveguide and resonator measurement techniques

2020 ◽  
Vol 12 (9) ◽  
pp. 892-899
Author(s):  
Z. E. Eremenko ◽  
A. I. Shubnyi ◽  
A. Y. Kogut ◽  
R. S. Dolia
Keyword(s):  
Complex Permittivity ◽  
Measurement Errors ◽  
Measurement Techniques ◽  
Circular Waveguide ◽  
Diffraction Effect ◽  
Measurement Sensitivity ◽  
High Loss ◽  
Dielectric Characterization ◽  
Coefficient Measurement ◽  
Complex Propagation

AbstractThe microwave waveguide and resonator methods are compared as applied to the experimental determination of the dielectric properties of high loss liquids. A differential microwave waveguide cavity for measuring high loss liquids complex permittivity in a small volume has been designed and studied. This cavity consists of two circular waveguide cells with central rods made of quartz and surrounded by high loss liquid tested. The cells have different lengths to eliminate complex propagation coefficient measurement errors due to the diffraction effect on the ends of the layered waveguide cells. We have measured the wave amplitude and phase coefficients for the waveguide cavity to estimate physical properties of a high loss liquid under test. The resonant frequencies and the Q-factor of a semi-disk dielectric resonator with high loss liquid filling a capillary have been measured. We have selected water-ethanol solutions as a high loss liquid under test for both techniques. We have determined the measurement sensitivity for these two techniques. The measuring results are discussed. Both the waveguide and resonator methods provide comparable sensitivity and can be successfully used for the complex permittivity characterization of high loss liquids in small volumes.

scholarly journals A Novel Method Based on Two Different Thicknesses of The Sample for Determining Complex Permittivity of Materials Using Electromagnetic Wave Propagation in Free Space at X-Band

2017 ◽  
Author(s):  
Cuong Ho manh ◽  
Yem Vu van
Keyword(s):  
Dielectric Loss ◽  
Loss Tangent ◽  
Complex Permittivity ◽  
Dielectric Loss Tangent ◽  
Free Space ◽  
Propagation Constant ◽  
High Loss ◽  
Transmission Coefficients ◽  
X Band ◽  
Complex Propagation

In this paper, we present a method for determining complex permittivity of materials using two different thicknesses of the sample placed in free space. The proposed method is based on the use of transmission having the same geometry with different thicknesses with the aim to determine the complex propagation constant (γ). The reflection and transmission coefficients (S11 and S21) of material samples are determined using a free-space measurement system. The system consists of transmit and receive horn antennas operating at X-band. The complex permittivity of materials is calculated from the values of γ, in turns received from S11 and S21. The proposed method is tested with different material samples in the frequency range of 8.0 – 12.0 GHz. The results show that the dielectric loss tangent of low-loss material samples, the more accuracy of complex permittivity. However, the complex permittivity is slightly effected by the dielectric loss tangent of high-loss of material samples.

scholarly journals Diffracting-grain identification from electron backscatter diffraction maps during residual stress measurements: a comparison between the sin2ψ and cosα methods

2019 ◽  
Vol 52 (4) ◽  
pp. 828-843 ◽  
Author(s):  
Dorian Delbergue ◽  
Damien Texier ◽  
Martin Lévesque ◽  
Philippe Bocher
Keyword(s):  
Residual Stress ◽  
Grain Size ◽  
Tilt Angle ◽  
Measurement Errors ◽  
Electron Backscatter Diffraction ◽  
Measurement Techniques ◽  
Single Exposure ◽  
X Ray ◽  
Electron Backscatter ◽  
Backscatter Diffraction

X-ray diffraction (XRD) is a widely used technique to evaluate residual stresses in crystalline materials. Several XRD measurement methods are available. (i) The sin2ψ method, a multiple-exposure technique, uses linear detectors to capture intercepts of the Debye–Scherrer rings, losing the major portion of the diffracting signal. (ii) The cosα method, thanks to the development of compact 2D detectors allowing the entire Debye–Scherrer ring to be captured in a single exposure, is an alternative method for residual stress measurement. The present article compares the two calculation methods in a new manner, by looking at the possible measurement errors related to each method. To this end, sets of grains in diffraction condition were first identified from electron backscatter diffraction (EBSD) mapping of Inconel 718 samples for each XRD calculation method and its associated detector, as each method provides different sets owing to the detector geometry or to the method specificities (such as tilt-angle number or Debye–Scherrer ring division). The X-ray elastic constant (XEC) ½S 2, calculated from EBSD maps for the {311} lattice planes, was determined and compared for the different sets of diffracting grains. It was observed that the 2D detector captures 1.5 times more grains in a single exposure (one tilt angle) than the linear detectors for nine tilt angles. Different XEC mean values were found for the sets of grains from the two XRD techniques/detectors. Grain-size effects were simulated, as well as detector oscillations to overcome them. A bimodal grain-size distribution effect and `artificial' textures introduced by XRD measurement techniques are also discussed.

Dielectric Metrology VIA Microwave Tomography: Present and Future

1994 ◽  
Vol 347 ◽  
Author(s):  
J.Ch. Bolomey ◽  
N. Joachimowicz
Keyword(s):  
Inverse Scattering ◽  
A Priori ◽  
Scattering Problem ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Inverse Scattering Problem ◽  
Dielectric Characterization ◽  
Sample Shape ◽  
Three Dimensional Configuration ◽  
Characterization Of Materials

ABSTRACTUntil now, the measurement techniques used for the dielectric characterization of materials require severe limitations in terms of sample shape, size and homogeneity. This paper considers the dielectric permittivity measurement as a non-linear inverse scattering problem. Such an approach allows to identify the quantities to be measured and suggests possible experimental arrangements. The problem is shown to be significantly simplified if the shape of the material is known and if some a priori knowledge of the averaged value of the permittivity in the material under test is available. Two test cases have been selected to illustrate the state of the art in solving such inverse problems. The first one consists of a two-dimensional configuration which is applicable to cylindrical objects, and the second one to a vector three-dimensional configuration applicable, for instance, to cubic samples. The main limitations of such an inverse scattering approach are discussed and expected improvements in the near future are analysed.

Broadband Dielectric Characterization of Aluminum Oxide (Al2O3)

2008 ◽  
Vol 5 (1) ◽  
pp. 2-7 ◽  
Author(s):  
Khalid Z. Rajab ◽  
Mira Naftaly ◽  
Edmund H. Linfield ◽  
Juan C. Nino ◽  
Daniel Arenas ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Aluminum Oxide ◽  
Time Domain ◽  
Measurement Techniques ◽  
Thz Spectroscopy ◽  
Dielectric Characterization ◽  
Dielectric Constant And Loss ◽  
Ir Frequencies ◽  
Cofired Ceramics

Applications for low-temperature cofired ceramics (LTCC) and high-temperature cofired ceramics (HTCC) are advancing to higher frequencies. In order to design ceramic microsystems and electronic packages, the electrical properties of materials must be well characterized over a broad frequency range. In this study, the dielectric properties of commercial aluminum oxide (Al2O3) with different glass loadings are characterized using three different measurement techniques: the split-post cavity, terahertz (THz) time-domain spectroscopy, and Fourier transform IR spectroscopy (FTIR). Specifically, the dielectric properties will be characterized from 10 GHz to IR frequencies. A split-post cavity was employed for determination of dielectric properties in the 10 GHz range. A broadband THz spectroscopy technique was used to characterize the specimens using measured time-domain transmission data. The dielectric constant and loss were extracted from the sample's frequency-domain transmission characteristics, providing data between 100 GHz and 2 THz. Additionally, FTIR was used to characterize the samples from ~33 to 3300 cm−1 (~1–100 THz). The measurements from the three techniques are compared, and dielectric constant and loss data will be presented for commercial and experimental ceramic systems from 10 GHz to IR frequencies.

scholarly journals Complex Permittivity Measurement of High-Loss Biological Material with Improved Cavity Perturbation Method in the Range of 26.5–40 GHz

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1200
Author(s):  
Jialu Ma ◽  
Zhe Wu ◽  
Qiong Xia ◽  
Shaomeng Wang ◽  
Jingchao Tang ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Perturbation Method ◽  
Cancer Cells ◽  
Complex Permittivity ◽  
Dielectric Constants ◽  
Rectangular Cavity ◽  
Ka Band ◽  
High Loss ◽  
Cavity Perturbation ◽  
High Dielectric

In this paper, we performed and designed a new rectangular cavity to identify and analyze the complex permittivity of two cancer cells (Breast-MDA231, Uveal melanoma) that have a high dielectric constant and dielectric loss. The rectangular cavity device is based on the improved cavity perturbation technology. The sample of the improved cavity perturbation device is placed at the position of a/n close to the wall of the cavity, where a is the wide side of the cavity and n is the positive even number. For high-loss biological materials, the improved cavity perturbation method has higher accuracy than the traditional cavity perturbation method. The results present that the relative dielectric constants of a single cell at Ka-band (26.5–40 GHz) are in the range 8–15, and the relative dielectric loss is 24–31. The information of the cancer cells at Ka-band waves can be helpful for further cancer detection and clinical treatment.

Measuring Failures and Correction Methods for Pneumatic Multi-Hole Probes

2012 ◽  
Author(s):  
Herwart T. Hoenen ◽  
Robert Kunte ◽  
Phillip Waniczek ◽  
Peter Jeschke
Keyword(s):  
Measurement Errors ◽  
Measurement Techniques ◽  
Axial Compressor ◽  
Correction Method ◽  
Gradient Field ◽  
Trailing Edge ◽  
Measurement Results ◽  
Real Flow ◽  
Hot Film ◽  
Probe Measurements

Systematic measurements have been performed in a free stream in order to analyse the measuring behaviour of pneumatic multi-hole probes in the gradient field of a wake of an airfoil. The five-hole probe was traversed in different axial distances from the trailing edge and the results were compared to PIV and hot film probe measurements. The direct comparison of the three measurement techniques shows that too small axial distances between a five-hole probe and an airfoil trailing edge introduce significant measurement errors. Different effects were analysed in order to evaluate their influence on the measuring results and to estimate the deviation from the real flow properties. The limitations of probe measurements and the influences of the probe on the flow field are discussed. It is explained how pneumatic multi-hole probe measuring data can be corrected in order to improve the measuring results. In order to demonstrate the suitability of the correction method for turbo machinery application it is applied to measurement results of an axial compressor test rig.

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