Industrial microwave sensors

Nyfors, Ebbe; Vainikainen, P.

doi:10.1109/mwsym.1991.147182

Cited by 220 publications

(214 citation statements)

References 15 publications

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“…Finding Optical Permittivity, ε ∝ : In general, the optical permittivity, ε ∝ is independent of frequency, f and temperature, T (Nyfors and Vainikainen, 1989). Thus, the ε ∝ of hydrogel is assumed as mixture expression:…”

Section: Dielectric Modelingmentioning

confidence: 99%

“…6 represents the mean activation energy, Q of bulk water and gives 18.3 kJ mol −1 compare with literature (Nyfors and Vainikainen, 1989) Table 4. This mean that the energy, Q released (or absorbed) per mole for the hydrogen bond are formed in PVA hydrogel, are less than the hydrogen bonds formed in pure water for entire frequency.…”

Section: Macroscopic Analysismentioning

confidence: 99%

See 1 more Smart Citation

Improved Dielectric Model for Polyvinyl Alcohol-Water Hydrogel at Microwave Frequencies

You¹,

Abbas

Khalid

et al. 2010

American Journal of Applied Sciences

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Problem statement: The study described rigorous dielectric modeling for Polyvinyl Alcohol (PVA)-water hydrogel mixture at microwave frequencies. Approach: A commercial openended coaxial sensor was used to measure the dielectric constant, loss factor and ionic conductivity, σ of PVA-water hydrogel mixture ranging concentration of 80-100% water content. Results: The sensor was operating between 0.13 and 20 GHz at and above of room temperature (25±1)°C. Indirectly, the relaxation time, τ, activation energy, Q and entropy change, ΔS of the hydrogel mixtures are determined based on linear fitting of measured data using Debye and Arrhenius approaches. Conclusion/Recommendations: Two main relaxation processes were found ranging 2-10 and 10-20 GHz, respectively. Dielectric dispersion is suggested to describe by combination of Cole-Davidson (CD) and Debye (Dy) processes. The results are discussed qualitatively based on bound states of water in hydrogel mixtures.

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Section: Dielectric Modelingmentioning

confidence: 99%

Section: Macroscopic Analysismentioning

confidence: 99%

Improved Dielectric Model for Polyvinyl Alcohol-Water Hydrogel at Microwave Frequencies

You¹,

Abbas

Khalid

et al. 2010

American Journal of Applied Sciences

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“…Disadvantages are the usually high degree of specialization and the simultaneous existence of several variables affecting the microwave measurement (temperature, density, moisture, structure, etc.) in material measurements [9].…”

Section: Investigating Properties Of Materials Using Microwave Cavitiesmentioning

confidence: 99%

Biomedical Sensing with Hydroxyapatite Ceramics in GHz Frequency Range

Korostynska

Gandhi

Mason

et al. 2013

KEM

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A.Al-Shamma'a@ljmu.ac.uk, e Tofail.Syed@ul.ie Keywords: Hydroxyapatite, GHz frequency range, biocompatible sensor, real-time pressure sensing in medical applications, piezoelectic and pyroelectric properties, powder and films.Abstract. Hydroxyapatite (HA) is a leading biocompatible material extensively used for bone implants as a porous ceramic graft and as a bioactive coating. Electrical characteristics of HA can be employed in implantable devices for real-time in vivo pressure sensor applications such as in knee or hip prosthesis. In particular, high piezo and pyroelectricity of HA, its polarisation by electron beam and selective adsorption of proteins on polarised domains indicate the potential for real-time biosensing applications of HA. For this purpose, a comprehensive understanding of the dielectric behaviour of different forms of HA over a frequency range relevant for biomedical sensing is critical. Such information for HA, especially its frequency dependent dielectric behaviour over the GHz range, is rare. To this end, we report on novel investigations of properties of HA in powder and film forms in the GHz frequency range.

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“…Microwave engineering requires precise knowledge on electromagnetic properties of materials at microwave frequencies since microwave communications are playing more and more important roles in military, industrial, and civilian life [1][2][3]. For these reasons, various microwave techniques, each with its unique advantages and constraints [1], are introduced to characterize the electrical properties of materials.…”

Section: Introductionmentioning

confidence: 99%

“…However, these methods require some sort of calibration before measurements [2]. This is because these methods are generally adapted to a specific application and sensitive to more than one variable.…”

Section: Introductionmentioning

confidence: 99%

A Simple Approach for Evaluating the Reciprocity of Materials Without Using Any Calibration Standard

Hasar¹,

Şimşek²

2009

PIER

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Abstract-A simple approach for evaluation of the reciprocity of materials using raw scattering parameter measurements is proposed. This approach not only reduces the overall measurement time but also eliminates the need for calibrating the measurement system since it uses calibration-independent measurements. We have derived a metric function for reflecting and nonreflecting cells, which are used to house the sample under test. This function does not depend on electrical properties of materials and their lengths, and whether the cell is reflecting. We have also investigated the effects of the sample length and air pockets between sample external surfaces and cell inner walls on the performance of the evaluation of sample reciprocity.

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Industrial microwave sensors

Cited by 220 publications

References 15 publications

Improved Dielectric Model for Polyvinyl Alcohol-Water Hydrogel at Microwave Frequencies

Improved Dielectric Model for Polyvinyl Alcohol-Water Hydrogel at Microwave Frequencies

Biomedical Sensing with Hydroxyapatite Ceramics in GHz Frequency Range

A Simple Approach for Evaluating the Reciprocity of Materials Without Using Any Calibration Standard

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