Geometrical Optics-Based Model for Dielectric Constant and Loss Tangent Free-Space Measurement

Haddadi, Kamel; Lasri, T.

doi:10.1109/tim.2013.2297811

Cited by 35 publications

(9 citation statements)

References 14 publications

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“…To use fabric as a substrate in RA, electrical properties of the used material should be known. There are certain methods used for extracting material properties e.g., coaxial probe method [21], waveguide method [22], cavity method [23], free space method [24], resonance method [25] and ridge-gap waveguide method [26]. The relative permittivities of the samples under test are extracted and validated by resonance method, which is further used in designing textile RA unit cell.…”

Section: Introductionmentioning

confidence: 99%

Practical Investigation of Different Possible Textile Unit Cell for a C-Band Portable Textile Reflectarray Using Conductive Thread

Tahseen¹,

Kishk²

2016

PIER B

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Abstract-Investigation of a unit cell in terms of reflected wave amplitude and phase, for designing linearly polarized single layer Textile-Reflectarray (TRA) at C-band, is presented. The relative dielectric constant of the material is extracted using resonance method, and a WLAN antenna is designed to verify the accuracy of extracted material parameter. An error of 5% is observed in the extracted dielectric constant, when performance of WLAN antenna is measured at WI-FI Band (2.4 GHz). The extracted dielectric constant is used in the unit cell designing for TRA at the C-band (5.8 GHz). The radiating element is made using laying technique with conductive thread. A square patch with a ring is selected after analyzing multiple geometries of the patch providing the required reflected phase range and low losses. By varying size of patch and ring of single layer unit cell in CST periodic environment, reflected phase range of 360 degrees is achieved, which is required for reflectarray (RA) designing. The solid copper ground plane at the bottom of unit cell is replaced with conductive shielded fabric with high level signal attenuation. Four different sizes of textile unit cells are fabricated using conductive thread, and the reflected phase and amplitude are measured using waveguide method. The simulated and measured results are compared when solid copper ground plane at the bottom of unit cell has been replaced with shielded fabric. The proposed method provides the first step towards designing flexible high gain textile reflectarrays.

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Section: Introductionmentioning

confidence: 99%

Practical Investigation of Different Possible Textile Unit Cell for a C-Band Portable Textile Reflectarray Using Conductive Thread

Tahseen¹,

Kishk²

2016

PIER B

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“…Many industrial processes require an instrumentation suitable for contactless methods and real-time on-line monitoring and control. Although microwave free-space techniques present features to address non-ionizing and low-power microwave nondestructive testing and evaluation (MNDT&E) applications in an industrial context, its transposition in an 2 of 11 industrial context still remains a challenge [7,8]. The use of focusing horn-lens antennas are not suitable as the material under test is usually one-sided.…”

Section: Introductionmentioning

confidence: 99%

Roll-to-Roll In-Line Implementation of Microwave Free-Space Non-Destructive Evaluation of Conductive Composite Thin Layer Materials

Koutsoukis¹,

Alic

Vavouliotis³

et al. 2021

Applied Sciences

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A free-space microwave nondestructive testing and evaluation module is developed for the low-power, non-ionizing, contactless, and real-time characterization of doped composite thin-film materials in an industrial context. The instrumentation proposed is built up with a handled vector network analyzer interfaced with corrugated horn antennas to measure the near-field complex reflection S11 of planar prepreg composite materials in a roll-to-roll in-line production line. Dedicated modeling and calibrations routines are developed to extract the microwave conductivity from the measured microwave signal. Practical extraction of the radiofrequency (RF) conductivity of thin film prepreg composite materials doped with nano-powders is exemplary shown at the test frequency of 10 GHz.

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“…[1]). There exist many different material characterization methods [2], and among them some popular methods are (presented roughly in order of increasing frequency): split-post dielectric resonators [2]- [3], coaxial probes [4], transmission lines [5], open-resonators [6]- [7], free-space methods [8]- [9], and Time Domain Spectroscopy (TDS) methods [10]. The open-resonators and free-space methods have been most widely used for measurements at millimeter-wave frequencies.…”

Section: Introductionmentioning

confidence: 99%

Assessing the Impact of Data Filtering Techniques on Material Characterization at Millimeter-Wave Frequencies

Shang

Ridler

et al. 2021

IEEE Trans. Instrum. Meas.

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This paper reports on an investigation into data filtering techniques for material characterization using a commercially available WR-15 (50-75 GHz) material characterization kit (MCK). The MCK uses a guided free-space method (operating like the conventional quasi-optical focused beam system) that enables measurement of S-parameters of dielectrics using a vector network analyzer (VNA). Multiple reflections and resonances exist in the MCK and they cannot be readily eliminated by calibration. To minimize these effects on extracting dielectric constant and loss tangent from the measured S-parameters, data filtering techniques (e.g. Savitzky-Golay filter and time-gating) can be adopted. A comparison of measurement results using these two techniques was carried out on five common dielectric materials. Generally, the results obtained using these two filtering techniques are consistent with each other, and the Savitzky-Golay filter offers better performance in the scenario where the specimen quality is not ideal. Three specimens were also measured using an open-resonator (operating at 36 GHz). There is generally good agreement between results from the MCK and the open-resonator.

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Geometrical Optics-Based Model for Dielectric Constant and Loss Tangent Free-Space Measurement

Cited by 35 publications

References 14 publications

Practical Investigation of Different Possible Textile Unit Cell for a C-Band Portable Textile Reflectarray Using Conductive Thread

Practical Investigation of Different Possible Textile Unit Cell for a C-Band Portable Textile Reflectarray Using Conductive Thread

Roll-to-Roll In-Line Implementation of Microwave Free-Space Non-Destructive Evaluation of Conductive Composite Thin Layer Materials

Assessing the Impact of Data Filtering Techniques on Material Characterization at Millimeter-Wave Frequencies

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