Measurements of Shielding Effectiveness of Textile Materials Containing Metal by the Free-Space Transmission Technique with Data Processing in the Time Domain

Polymer composite films containing fillers comprising quasi‐1D van der Waals materials, specifically transition metal trichalcogenides with 1D structural motifs that enable their exfoliation into bundles of atomic threads, are reported. These nanostructures are characterized by extremely large aspect ratios of up to ≈106. The polymer composites with low loadings of quasi‐1D TaSe3 fillers (<3 vol%) reveal excellent electromagnetic interference shielding in the X‐band GHz and extremely high frequency sub‐THz frequency ranges, while remaining DC electrically insulating. The unique electromagnetic shielding characteristics of these films are attributed to effective coupling of the electromagnetic waves to the high‐aspect‐ratio electrically conductive TaSe3 atomic‐thread bundles even when the filler concentration is below the electrical percolation threshold. These novel films are promising for high‐frequency communication technologies, which require electromagnetic shielding films that are flexible, lightweight, corrosion resistant, inexpensive, and electrically insulating.

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“…In order to improve the reliability of the collected data, additional time‐domain gating was applied (see refs. [ 31,64–66 ] for more details).…”

Section: Methodsmentioning

confidence: 99%

“…The measurement with an empty optical path and the measurement with a metal plate allow one to calculate the actual transmission and reflection coefficients, respectively. In order to improve the reliability of the collected data additional time-domain gating was applied (see [31,[59][60][61] for more details).…”

Section: Massmentioning

confidence: 99%

Electrically Insulating Flexible Films with Quasi‐1D van der Waals Fillers as Efficient Electromagnetic Shields in the GHz and Sub‐THz Frequency Bands

et al. 2021

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“…This method does not account for diffracted and reflected fields; therefore, the measured data is then usually treated with a timedomain gating algorithm to get accurate results. 105 Dvurechenskaya et al proposed a time domain method to extract the shielding effectiveness of a textile using the free-space method. According to the method proposed in the paper, the first step is to determine the time domain counterpart fs 21 g of the measured frequency domain transmission coefficient S 21 using:…”

Section: Free-space Methodsmentioning

confidence: 99%

Electromagnetic Interference (EMI): Measurement and Reduction Techniques

Mathur

Raman

2020

Journal of Elec Materi

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Electromagnetic interference (EMI) is one of the biggest challenges faced during the production of any electronic device. The effect on the performance of the instrument due to these inevitable interferences must be carefully measured to understand and quantify the electromagnetic compatibility (EMC) of the instrument under test. If the EMI profile of the system does not meet the accepted standards, then it becomes necessary to take measures to reduce the influence of these unwanted interferences so that the equipment can be used in the real world. Unfortunately, research and studies on EMI and EMC have not received their due attention from the scientific community. Moreover, the literature available for this area of research is scattered where different sources provide information on one or more (but not all) aspects of EMI/EMC while ignoring the others. With the objective of encompassing this extremely significant area of research in its entirety, this review presents both EMI measurement techniques and EMI reduction techniques in detail. EMI measurement techniques are presented under two sections that deal with emission testing and immunity testing, respectively. Herein, EMI reduction techniques are presented under four sections, where electromagnetic shielding has been given special attention under which various methods used by the scientific community to measure the shielding effectiveness of a material or microwave absorber and its application in EMI reduction are illustrated. This is followed by EMI filters, circuit topology modification and spread spectrum. This review can help students and young scientists in this area to get an idea of the ways to conduct EMI tests as well as the ways that can be employed to reduce the EMI of the system, depending on the application.

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“…Time-gating is usually applied to free-space measurements to separate the desired signal from spurious reflections generated elsewhere in the measurement system or within the sample [16]. A Kaiser-Bessel window is introduced in the time-domain so that signals that are not within the bandpass window are discarded.…”

Section: A Time-gatingmentioning

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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Measurements of Shielding Effectiveness of Textile Materials Containing Metal by the Free-Space Transmission Technique with Data Processing in the Time Domain

Cited by 21 publications

References 13 publications

Electrically Insulating Flexible Films with Quasi‐1D van der Waals Fillers as Efficient Electromagnetic Shields in the GHz and Sub‐THz Frequency Bands

Electrically Insulating Flexible Films with Quasi‐1D van der Waals Fillers as Efficient Electromagnetic Shields in the GHz and Sub‐THz Frequency Bands

Electromagnetic Interference (EMI): Measurement and Reduction Techniques

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

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