Complex permittivity measurement using capacitance method from 300kHz to 50MHz

Raymond, Wong Jee Keen; Chakrabarty, Chandan Kumar; Hock, Goh Chin; Ghani, Aminuddin Ab

doi:10.1016/j.measurement.2013.06.039

Cited by 27 publications

(8 citation statements)

References 15 publications

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“…Permittivity can be calculated via (1). Often, relative permittivity should be used to express electrical properties of materials, and relative permittivity of tissue is the ratio of permittivity of tissue and the permittivity of vacuum [31]; that is, = / 0 . The relative permittivity of rat tissues is shown in Table 1.…”

Section: Resultsmentioning

confidence: 99%

Effective Permittivity of Biological Tissue: Comparison of Theoretical Model and Experiment

Ning

Zhang

2017

Mathematical Problems in Engineering

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Permittivity of biological tissue is a critical issue for studying the biological effects of electromagnetic fields. Many theories and experiments were performed to measure or explain the permittivity characteristics in biological tissue. In this paper, we investigate the permittivity parameter in biological tissues via theoretical and experimental analysis. Firstly, we analyze the permittivity characteristic in tissue by using theories on composite material. Secondly, typical biological tissues, such as blood, fat, liver, and brain, are measured by HP4275A Multi-Frequency LCR Meter within 10 kHz to 10 MHz. Thirdly, experimental results are compared with the Bottcher-Bordewijk model, the Skipetrov equation, and the Maxwell-Gannett theory. From the theoretical perspective, blood and fat are regarded as the composition of liver and brain because of the high permittivity in blood and the opposite in fat. Volume fraction of blood in liver and brain is analyzed theoretically, and the applicability and the limitation of the models are also discussed. These results benefit further study on local biological effects of electromagnetic fields.

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Section: Resultsmentioning

confidence: 99%

Effective Permittivity of Biological Tissue: Comparison of Theoretical Model and Experiment

Ning

Zhang

2017

Mathematical Problems in Engineering

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“…The dielectric loss tangent is proportional to the dielectric loss [4][5][6][7][8][9][10][11][12][13]. In addition, the complex dielectric constant due to the parallel plate capacitor due to the difference in materials is described in the literature [14], the difference in the frequency characteristics of pure water and blood is described in [15], and the effects of weak microwave exposure are described in [16].…”

Section: Half-power Depthmentioning

confidence: 99%

System for Monitoring Avian Cardiac Output and Breathing Patterns Using Transmission-Type Microwaves

Nakajima¹,

Kuwahira²,

Hata³

2022

J Multimed Inf Syst

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We report the development of a non-contact monitoring device for avian cardiac output and breathing patterns based on the anterior thoracic air sac pressure that uses transmission-type microwaves (2,400−2,500 MHz, continuous wave). Since the phase waveform represents the dielectric constant change, the phase reflects −j/ωc and the dielectric constant change is related to blood flow. The magnitude waveform is reflected from the electronic resistance of tissues due to the expansion of the anterior thoracic air sac, which mainly consists of the thoracic wall. To confirm these waveforms, pigeons and chickens were used for testing. To validate the output waveforms of the developed transmission-type microwave device, data from esophageal catheters and pressure sensors in the anterior thoracic air sac, abdominal air sac, and intraoral cavity were obtained. The waveform for the esophageal catheter, where electrocardiogram electrodes and an angular velocity sensor were installed, correlates with cardiac output. A heart sound microphone was used to confirm the closing sound of the arterial and mitral valves. The experimental results confirm that a linear waveform synchronized with the cardiac blood flow and the anterior thoracic air sac pressure of birds was obtained using transmission-type microwaves. The proposed device, which can monitor cardiac output and respiratory patterns, may enable the early screening of cytokine storms caused by avian influenza viruses. Existing devices use Doppler radar in the 10 to 77 GHz band; these high frequencies are reflected by the chest wall and do not reach deep into body, making it impossible to monitor the blood flow inside the body.

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“…S 11c e 2γ a l a1 S 12c e γ a l a1 S 21c e γ a l a1 S 22c (9) and apply the well-known NRW algorithm [26,27] to obtain the reflection coefficient at the air-sample boundary…”

Section: Classical Approachmentioning

confidence: 99%

“…Its real part ε r is related to the energy stored, while the imaginary part is tied in with the dielectric loss and conductivity of a material due to an external field. Depending on the frequency of interest, the permittivity is measured using various techniques [1,5,7,8], as e.g., capacitance method [9], resonant cavities [10], free space measurements [11], time-domain spectroscopy [12], transmission/ reflection (T/R) and reflection-only methods [13,14].…”

Section: Introductionmentioning

confidence: 99%

Errors in Broadband Permittivity Determination Due to Liquid Surface Distortions in Semi-Open Test Cell

Kalisiak

Wiatr

2021

Remote Sensing

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We study how surface distortions of liquid samples due to a meniscus and a tilt of a semi-open coaxial test cell affect errors in a broadband permittivity determination. The study is based on the scattering parameters, obtained using the electromagnetic simulations of samples with flat and distorted surfaces in a broad frequency range up to 18 GHz. The parameters are processed with the classic Nicolson–Ross–Weir (NRW) method and our new meniscus removal technique. We analyze the errors for several samples of different properties, such as distilled water and propan-2-ol. The results show that the meniscus removal technique is more robust and provides smaller errors in the permittivity determination compared to the classic NRW method. The effect of the cell tilt, to our best knowledge, has not been considered in the literature yet.

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Complex permittivity measurement using capacitance method from 300kHz to 50MHz

Cited by 27 publications

References 15 publications

Effective Permittivity of Biological Tissue: Comparison of Theoretical Model and Experiment

Effective Permittivity of Biological Tissue: Comparison of Theoretical Model and Experiment

System for Monitoring Avian Cardiac Output and Breathing Patterns Using Transmission-Type Microwaves

Errors in Broadband Permittivity Determination Due to Liquid Surface Distortions in Semi-Open Test Cell

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