Selection Of Dielectric Material Research Articles

Customized flexible iontronic pressure sensors: Multilevel microstructures by 3D-Printing for enhanced sensitivity and broad pressure range

Flexible capacitive pressure sensors stand out for their energy efficiency, rapid responsiveness, and exceptional durability, with their performance hinging on the intricate design of microstructures and the strategic selection of dielectric materials. However, creating cost-effective and practical fabrication methods for these components continues to pose a significant challenge. This study unveils an innovative iontronic flexible pressure sensor that integrates an ionic layer with sophisticated multilayer microstructures, setting new benchmarks in pressure sensing technology. The sensor operates within an expansive pressure range, achieving sensitivities as high as 92.14 kPa−1 at pressures from 0 to 50 kPa, and 22.96 kPa−1 at pressures ranging from 50 to 800 kPa, demonstrating extraordinary sensitivity. It also achieves an exceptionally low detection limit of 6.67 Pa and features swift response times of 56 ms to activate and 18 ms to deactivate. Enhanced by the addition of CuSO4, the sensor not only withstands freezing conditions but also significantly boosts sensitivity. Moreover, this sensor is capable of detecting human joint movements and subtle pressure fluctuations under high-pressure conditions, suggesting a breakthrough in the field. This research presents a simple, reliable, and cost-efficient method for developing flexible iontronic pressure sensors, poised to revolutionize applications in wide-ranging pressures and adverse temperature environments.

Effect of dielectric material on the uniformity of nanosecond pulsed dielectric barrier discharge

Dielectric barrier discharge (DBD) is considered as a promising technique to produce large volume uniform plasma at atmospheric pressure, and the dielectric barrier layer between the electrodes plays a key role in the DBD processes and enhancing discharge uniformity. In this work, the uniformity and discharge characteristics of the nanosecond (ns) pulsed DBD with dielectric barrier layers made of alumina, quartz glass, polycarbonate (PC), and polypropylene (PP) are investigated via discharge image observation, voltage-current waveform measurement and optical emission spectral diagnosis. Through analyzing discharge image by gray value standard deviation method, the discharge uniformity is quantitatively calculated. The effects of the space electric field intensity, the electron density (N e), and the space reactive species on the uniformity are studied with quantifying the gap voltage U g and the discharge current I g, analyzing the recorded optical emission spectra, and simulating the temporal distribution of N e with a one-dimensional fluid model. It is found that as the relative permittivity of the dielectric materials increases, the space electric field intensity is enhanced, which results in a higher N e and electron temperature (T e). Therefore, an appropriate value of space electric field intensity can promote electron avalanches, resulting in uniform and stable plasma by the merging of electron avalanches. However, an excessive value of space electric field intensity leads to the aggregation of space charges and the distortion of the space electric field, which reduce the discharge uniformity. The surface roughness and the surface charge decay are measured to explain the influences of the surface properties and the second electron emission on the discharge uniformity. The results in this work give a comprehensive understanding of the effect of the dielectric materials on the DBD uniformity, and contribute to the selection of dielectric materials for DBD reactor and the realization of atmospheric pressure uniform, stable, and reactive plasma sources.

Impact of sole layer duple substrates on GA-based optimised graphene antennas for THz applications

The widespread use of graphene patch antennas is escalating as evidence of their applicability in areas like 6 G communications and THz spectroscopy. Geometric uncertainty and fabrication issues while downsizing makes terahertz antenna design problematic. Graphene's electromagnetic and mechanical qualities make it ideal for miniaturizing antennas for Terahertz use. In the THz spectrum, a graphene antenna requires careful dielectric material selection since performance fall, especially efficiency. This paper compares dual band multi-layered genetic algorithm-based optimized antennas for the THz applications, especially spectroscopy and 6 G utilizing sole layer duple substrates concept, i.e., two distinct substrates at the same level between the ground and patch. Different antennas are designed using various substrates like Rogers RO3010, RO3210, RT5880, RT5880LZ, TMM 13i, Taconic TLY-3, RF-10, Silicon, & Teflon. Two segments of four antennas are planned; one has silicon as a common substrate with four additional materials, and another has Teflon. The proposed antenna's performance is assessed in terms of bandwidth, beamwidth, directivity, efficiency, gain, radiation pattern, return loss, and VSWR. The results reveal that Silicon and Rogers RT5880 LZ substrates-based antenna perform better in a segment I, with bandwidth (GHz) of 150.1 and 156.9, directivity (dBi) of 5.93 and 4.23, efficiency (%) of 76.65 and 78.98, and gain (dB) of 4.97 and 3.3. While in segment II, Teflon and Taconic RF-10-based antenna perform better with features 158 and 198 bandwidth, 6.43 and 4.43 directivity, 74 and 83 efficiency, and 4.67 and 3.65 gain.

Dielectric‐Based Metamaterials for Near‐Perfect Light Absorption

AbstractThe emergence of metamaterials and their continued prosperity have built a powerful working platform for accurately manipulating the behavior of electromagnetic waves, providing sufficient possibility for the realization of metamaterial absorbers with outstanding performance. However, metamaterial absorbers composed of metallic materials typically possess many unfavorable factors, such as non‐adjustable absorption, easy oxidation, low‐melting, and expensive preparation costs. The selection of dielectric materials provides excellent alternatives due to their remarkable properties, thus dielectric‐based metamaterial absorbers (DBMAs) have attracted much attention. To promote breakthroughs in DBMAs and guide their future development, this work systematically and deeply reviews the recent research progress of DBMAs from four different but progressive aspects, including physical principles; classifications, material selections and tunable properties; preparation technologies; and functional applications. Five different types of theories and related physical mechanisms, such as Mie resonance, guided‐mode resonance, and Anapole resonance, are briefly outlined to explain DBMAs having near‐perfect absorption performance. Mainstream material selections, structure designs, and different types of tunable DBMAs are highlighted. Several widely utilized preparation methods for customizing DBMAs are given. Various practical applications of DBMAs in sensing, stealth technology, solar energy absorption, and electromagnetic interference suppression are reviewed. Finally, some key challenges and feasible solutions for DBMAs’ future development are provided.

Natural Silkworm Cocoon-Based Hierarchically Architected Composite Triboelectric Nanogenerators for Biomechanical Energy Harvesting.

Silk-based triboelectric nanogenerators (TENGs) have been demonstrated as an ideal platform for self-powered systems. The source of silk, Bombyx mori, entails a valuable ingredient, sericin (SS), viewed as a binder in composites. Interestingly, SS is rich in the amorphous region, possibly resulting in triboelectrification enhancement between the amorphous region and the crystallization region when subject to external pressure. However, most researchers remove the SS component when designing silk-TENGs to eliminate immunological responses as implantation in vivo through complicated degumming, rehydration, and dialysis procedures. Herein, integral SS retention was utilized to fabricate silk-TENGs without affecting the output performance. We designed, for the first time, an ultra-robust and natural silkworm cocoon layer (SCL)/polydimethylsiloxane (PDMS)-TENG as an energy harvester to scavenge waste energy from human motions. The working mechanisms and influence of operational parameters are explored and studied. Working in the contact-separation mode, the electrical outputs of the SCL/PDMS-TENG in terms of open-circuit voltage, short-circuit current, and power density reaches 126 V, 3 μA, and 216 mW/m2, respectively. The integrated self-charging TENG is demonstrated to power small electronic electronics and monitor human motions. This work widens a new dielectric material selection with SS retention to boost the output performance of TENGs for practical applications.

Landau Damping in Hybrid Plasmonics.

The Landau damping (LD) mechanism of the localized surface plasmon (LSP) decay is studied for the hybrid nanoplasmonic (metal core/dielectric shell) structures. It is shown that LD in hybrid structures is strongly affected by the permittivity and the electron effective mass in the dielectric shell in accordance with previous observations by Kreibig, and the strength of LD can be enhanced by an order of magnitude for some combinations of permittivity and effective mass. The physical reason for this effect is identified as an electron spillover into the dielectric where the electric field is higher than that in the metal and the presence of quasi-discrete energy levels in the dielectric. The theory indicates that the transition absorption at the metal-dielectric interface is a dominant contribution to LD in such hybrid structures. Thus, by judicious selection of dielectric material and its thickness, one can engineer decay rates and hot carrier production for important applications, such as photodetection and photochemistry.

Tailoring Trap Density of States through Impedance Analysis for Flexible Organic Field‐Effect Transistors

AbstractThe selection of dielectric material impacts the dielectric/semiconductor (D/S) interface which plays a significant role in defining the device performance. Hence, investigation of the D/S interfacial defects and trap states is essential for improving the device performance and designing new semiconductor and dielectric materials for organic field effect transistors (OFET). Here, the trap density of states (DOS) at the interface is investigated by impedance spectroscopy (IS). OFETs are fabricated with three different dielectric combinations and the highest mobility is found to be 0.12 cm2 V−1 s−1. Detailed analysis of the semiconductor thin film and the D/S interface is performed by atomic force microscopy, photoluminescence, time‐resolved photoluminescence and is found consistent with the DOS analysis. This work validates that IS can be utilized as a prospective DOS analysis method for OFET applications. Finally, for evaluating the potential application of the device architecture toward developing flexible electronic circuit components, the device is fabricated on a flexible substrate and the mechanical stability is examined by subjecting the device to a strain of 2.5%. The device shows no significant degradation in operation, confirming its practical utility.

Investigation into the Selection of Dielectric Material using MCDM Methodologies for MEMS Switches with High Power

This paper presents MCDM techniques (TOPSIS and VIKOR) for determining the optimum dielectric material for MEMS technology based high power capacitive switches. These techniques are used for picking the best material from a given set of materials under some given criterion. The capacitance ratio and dielectric leakage current which are important parameters in obtaining the good RF-response of a switch have been taken into consideration along with other parameters like thermal expansion, heat dissipation and melting point for choosing the best material. Under high power condition, chosen material must have lowest value of TCE, highest possible thermal conductivity, highest melting point, along with highest value of electrical resistivity and relative permittivity for good RF response. The result of both the methods shows that AlN is the best material followed by TiO2. Kindly check and confirm the inserted country name in affiliation 1 is correcly identified. Yes, It is correct.

Dielectric Material Selection for High Capacitance Ratio and Low Loss in MEMS Capacitive Switch using Ashby’s Methodology

The performance of the RF MEMS capacitive switch is majorly decided on capacitance ratio and loss in the dielectric layer as they decide the isolation (in dBs) in off condition. The capacitances in a MEMS capacitive switch in pull-up and pull-down states are used for deciding the capacitance ratio. In this article, we have presented a method to find out the best dielectric material using Ashby’s methodology for high capacitance ratio and low loss thus high isolation in switch off condition. Firstly, a database of 10 mostly employed dielectric materials have been created, and then, material indices are derived using material properties such as dielectric constant, resistivity, conductivity, and loss tangent which have been used in the selection of dielectric material. Through the study it is observed that to have a high capacitance ratio and low loss in dielectrics, the down capacitance should always be much greater than pull-up capacitance and tangent loss must be kept at possible minimum. This method will be highly useful in the selection of the best dielectric material by switch designers.

A high humidity-resistive triboelectric nanogeneratorviacoupling of dielectric material selection and surface-charge engineering

Dielectric material selection coupled with surface-charge engineering is demonstrated to effectively improve the output performance of triboelectric nanogenerators in a high humidity environment.

Influence of dielectric materials on discharge characteristics of coaxial DBD driven by nanosecond pulse voltage

The dielectric material is one of the important influencing factors for the dielectric barrier discharge (DBD) characteristics and its application effects. The glass, quartz, polycarbonate (PC), and polytetrafluoroethylene (PTFE) materials are selected as dielectric materials of a coaxial DBD reactor. A nanosecond (ns) pulse power supply is used to drive the coaxial DBD reactors and the influences of dielectric materials on the optical, electrical, and temperature characteristics of DBDs are recorded. The mechanisms of the effects of the dielectric materials on the DBD characteristics are analysed by equivalent electrical model and heat conduct model. From the observation of the discharge, all of the discharges are in the diffuse mode without filament and the coaxial DBD with glass dielectric barrier are more homogenous. With the electrical analysis, it is found that the glass dielectric barrier with larger relative permittivity compared with the other materials leads to a better discharge uniformity and a higher power deposition in gap. At the same applied voltage, the coaxial DBD reactor with glass dielectric barrier also has the highest energy efficiency, which can reach 70.8% at 24 kV peak applied voltage. The operation temperatures of the coaxial DBD reactors after 900 s discharge with different dielectric materials are compared. The coaxial DBD reactor with glass dielectric barrier has the highest outside wall temperature at 78.0 °C. The reactor with PTFE dielectric barrier has the lowest operation temperature at 58.2 °C. With the heat conduct analysis, the results show that the coaxial DBD reactor with glass dielectric barrier has the highest the inner barrier tube temperature at 137.9 °C and has the lowest heat loss power rate at 29.2% under thermal balance. The reported work provides important reference for the selection of dielectric materials for DBD reactors and for the optimization in the industrial application.

The Role of Silicon-Based Nanofillers and Polymer Crystallization on the Breakdown Behaviors of Polyethylene Blend Nanocomposites

Good breakdown strength is an important feature for the selection of dielectric materials, especially in high-voltage engineering. Although nanocomposites have been shown to possess many promising dielectric properties, the breakdown strength of nanocomposites is often found to be negatively affected. Recently, imposing nonisothermal crystallization processes on polyethylene blends has been demonstrated to be favorable for breakdown strength improvements of dielectric materials. In an attempt to increase nanocomposites’ voltage rating, this work reports on the effects of nonisothermal crystallization (fast, moderate and slow crystallizations) on the structure and dielectric properties of a polyethylene blend (PE) composed of 80% low density polyethylene and 20% high density polyethylene, added with silicon dioxide (SiO2) and silicon nitride (Si3N4) nanofillers. Through breakdown testing, the breakdown performance of Si3N4-based nanocomposites was better than SiO2-based nanocomposites. Since nanofiller dispersion within both nanocomposite systems was comparable, the enhanced breakdown performance of Si3N4-based nanocomposites is attributed to the surface chemistry of Si3N4 containing less hydroxyl groups than SiO2. Furthermore, the breakdown strength of SiO2-based nanocomposites and Si3N4-based nanocomposites improved, with the DC breakdown strength increasing by at least 12% when both the nanocomposites were subjected to moderate crystallization rather than fast and slow crystallizations. This is attributed to changes in the underlying molecular conformation of PE in addition to water-related effects. These results suggest that apart from changes in the nanofiller surface chemistry, changes in the underlying molecular conformation of polymers are also important to improve the breakdown performance of nanocomposites.

Wireless Network Enhancement in the Arctic by Selection of Dielectric Materials of Rooms

The Arctic is of fundamental military-strategic importance for Russia. The development of the Arctic without an advanced telecommunication infrastructure is very difficult. To supply working in the Arctic employees with universal means of communication, it is the most efficient to use wireless communication band between 2.4 GHz and 5 GHz. Facilities, where radio telecommunication equipment in the Arctic works, have walls consisting of a multilayer structure. There is the problem of organizing communication of good quality. In such rooms, the best method is to use wireless networks using MIMO technology. We have developed a theory that allows us to determine the time Interflection T based on the determination of the dielectric constant of multilayer materials. In this case, problems arise in determining this coefficient. We propose to use the well-known method of short circuit and idling. We conducted a large number of measurements to determine the dielectric constant of various materials. We used this value to calculate the time T. In the future, we made adjustments to the premises by changing the size and amount of multilayer materials. Experimental results in the range from 2.4 GHz to 5 GHz showed that the data transfer rate increased by 5-10% when we performed the calculation of time Interflection and processed the room with multilayer materials. The proposed method is applicable indoors to build a wireless LAN standard IEEE 802.11 n.

Investigation on Dielectric Material Selection for RF-MEMS Shunt Capacitive Switches Using Ashby, TOPSIS and VIKOR

In this paper, different material selection techniques like Ashby, TOPSIS and VIKOR have been used to select the best dielectric material for RF-MEMS switches with low power consumption. These methods help in choosing the optimum material from the available pool of materials. The dielectric material should be selected such that RF-MEMS capacitive switch should have good RF response, high thermal conductivity, low thermal coefficient of expansion, and low leakage current. For this purpose, the concerned material indices should have high value of relative permittivity, high value of electrical resistivity, low value of thermal coefficient of expansion, and high value of thermal conductivity. The presence of trade-offs led to no conclusive selection in case of Ashby’s method. Following Ashby’s method, TOPSIS and VIKOR method were used to select the optimum material. The end results suggest that TiO2 is the most suitable materials for shunt capacitive RF-MEMS switches.

Selection of dielectric material for producing diffuse dielectric barrier discharge plasma at atmospheric pressure

Abstract We report the effect of dielectric layer and its selection criterion to produce diffuse dielectric barrier discharge plasma at atmospheric pressure. The dielectric barriers over electrodes are used to prevent glow-to-arc transition by limiting growth of discharge current. We have analyzed the dielectric properties such as secondary electron emission, dielectric constant, dielectric thickness etc in order to get better power efficiency at breakdown. It is observed that a thin dielectric layer with high dielectric constant is suitable for lowering the breakdown voltage. During one of our experiments, planar-surface discharge plasma was produced with the use of epoxy resin dielectric-covered stripe electrodes. High-voltage high frequency signal was applied between the electrodes to produce the discharge. It is observed that the discharge remain stable & uniform in our parametric range. However, after prolonged discharge operation, degradation of dielectric layer was observed in the form of powder formation over the dielectric insulation. SEM analysis reveals that the powder contains individual as well as cluster of particles of micrometer size dimension. Such micro-particle formation may be useful for some material and biomedical applications, however in other way degraded dielectric would lead to spark formation in plasma. In this context, theoretical and experimental analysis of our results is presented in this paper.

Design of capacitive voltage divider for measuring ultrafast voltages

The aim of this paper is to consider and analyze design of capacitive voltage divider for measuring ultrafast voltage occurrence. Measuring pulse voltages by means of a capacitive divider in nanosecond range is affected by problems related to the construction of the divider and materials used. However, an appropriate constructive solution could minimize the budget of measuring uncertainty of the measurement pertaining to parasitic inductivity and capacitance. Consequently, the right selection of dielectric materials could offset the effects of high-voltage and low-voltage frequency characteristics of the capacitor. Four types of capacitive dividers have been constructed for the purpose of this paper. The high-voltage capacitor of each divider is a gas capacitor (intended to avoid both electrostatic and electrodynamic influence on measurement uncertainty). Ultrafast pulse response is measured by dividers constructed in this way, and compared with the corresponding response obtained from numerical simulations.

Analysis of material selection on dielectric metasurface performance.

Dielectric metasurfaces are ultra-thin devices that can shape optical wavefronts with extreme control. While an assortment of materials possessing a wide range of dielectric constants have been proposed and implemented, the minimum dielectric contrast required for metasurfaces to achieve high-efficiency performance, for a given device function and feature size constraint, is unclear. In this Article, we examine the impact of dielectric material selection on metasurface efficiency at optical frequencies. As a model system, we design transmissive, single-layer periodic metasurfaces (i.e., metagratings) using topology optimization, and we sweep device thickness and light deflection angle for differing material types. We find that for modest deflection angles below 40 degrees, materials with relatively low dielectric constants near 4 can be used to produce metagratings with efficiencies over 80%. However, ultra-high-efficiency devices designed for large deflection angles and multiple functions require materials with high dielectric constants comparable to silicon. We also identify, for all materials, a minimum device thickness required for optimal metagrating performance that scales inversely with dielectric constant. Our work presents materials selection guidelines for high-performance metasurfaces operating at visible and infrared wavelengths.

An investigation of dielectric material selection of RF-MEMS switches using Ashby’s methodology for RF applications

This paper presents a dielectric material selection methodology for RF-MEMS switch used for radio frequency applications. Here Ashby's material selection approach is used to optimize the performance indices of RF-MEMS switch such as dielectric charging, stability, hold down voltage and RF performance. In this work, dielectric constant (źr), electrical resistivity (ź), thermal conductivity (ź), thermal expansion coefficient (ź), Young's Modulus (E) are chosen as material indices of dielectric layer in RF-MEMS switch to evaluate the various performance indices. The Ashby's material selection charts shows that Al2O3 and SiN are the best suitable material for dielectric layer in RF-MEMS switches to exhibit improved performance for radio frequency applications.

The Effect of Changing Substrate Material and Thickness on the Performance of Inset Feed Microstrip Patch Antenna

In order to design a microstrip patch antenna at first the designer is to select the substrate material and it’s thickness. So, if the designer has a clear conception about the effect of changing substrate material and it’s thickness on the performance of the antenna, it will be easier to design an antenna. Appropriate selection of dielectric material and it’s thickness is an important task for designing a microstrip patch antenna. This paper represents that how antenna performance changes when we vary substrate material and it’s thickness. The designed inset feed rectangular microstrip patch antenna operates at 2.4GHz (ISM band).

Dielectric material selection of microstrip patch antenna for wireless communication applications using Ashby's approach

In this paper, material selection has been done for dielectric substrate material in microstrip patch antenna (MPA) for three distinct classes of wireless communication applications using Ashby's approach. This material selection procedure is based on the creation and evaluation of Ashby's chart of different material indices. These material indices in turn affect the device performance indices, which decide the best possible dielectric material to be used as substrate for MPAs. In this work, quality factor, relative permittivity, and temperature coefficient of resonant frequency are chosen as material indices of MPA's dielectric substrate to get relevant performances. Ashby's selection chart shows that 0.75MgAl2O4–0.25TiO2material for millimeter waves applications, Ca[(L1/3Nb2/3)0.85Ti0.15]O3−δfor mobile base station applications, and (Ba0.95Ca0.05)O–Sm2O3–4.5TiO2ceramic for mobile phone miniaturization applications are the promising materials that allows best overall performance in MPAs for wireless communication.