Parallel Metal Plates Research Articles

Measurement of Dielectric Liquid Electrification in the Shuttle System with Two Parallel Electrodes

In this paper, a device with swinging plate electrodes has been proposed to measure contact electrification of a liquid sample. The proposed structure is composed of two parallel metallic plates immersed in a dielectric liquid. One of the plates is swinging with a constant frequency in a range from 0.4 to 4 Hz. The paper investigates the dependence in time and frequency of electrode velocity and streaming electrification. The measured current occurs for a very low intermittent velocity of less than 10 mm/s. In this range, the electrification current is around 50 pA. For higher velocities of up to 150 mm/s, the current is at the level of 1200 pA. The time–frequency characteristic using short-time Fourier transform shows no temporal changes in the frequency spectrum. The dependence of electrification on shuttle speed was calculated and it can be approximated with a second order polynomial model with the determination coefficient higher than 0.9. The advantage of the sensor is the ability to measure electrification phenomena without the necessity of having rotating electrodes or having a large volume of flowing liquids.

Unsteady MHD Couette viscous fluid flow through silver metallic parallel plates with an inclined magnetic field and angular velocity subjected to constant suction at lower plate

Abstract In this paper, we discussed unsteady magneto hydrodynamic incompressible viscous couette flow along the silver metallic parallel plates in which constant periodic suction takes place at the bottom porous silver metallic shield subjected to the magnetic field with inclination along with the rotation of system. By means of appropriate choice of stream function we obtained exact solution analytically. Axial Velocity component and radial Velocity component are obtained from the analytical solution. Velocity profiles like axial and transverse are examined for different parameters α , K r , M a n d ω t . The effects of Magnetic parameter, Suction Reynolds number and Rotation parameter on the plates are discussed and illustrated graphically.

A system for probing Casimir energy corrections to the condensation energy

In this article, we present a nanoelectromechanical system (NEMS) designed to detect changes in the Casimir energy. The Casimir effect is a result of the appearance of quantum fluctuations in an electromagnetic vacuum. Previous experiments have used nano- or microscale parallel plate capacitors to detect the Casimir force by measuring the small attractive force these fluctuations exert between the two surfaces. In this new set of experiments, we aim to directly detect the shifts in the Casimir energy in a vacuum due to the presence of the metallic parallel plates, one of which is a superconductor. A change in the Casimir energy of this configuration is predicted to shift the superconducting transition temperature (Tc) because of the interaction between it and the superconducting condensation energy. In our experiment, we take a superconducting film, carefully measure its transition temperature, bring a conducting plate close to the film, create a Casimir cavity, and then measure the transition temperature again. The expected shifts are smaller than the normal shifts one sees in cycling superconducting films to cryogenic temperatures, so using a NEMS resonator in situ is the only practical way to obtain accurate, reproducible data. Using a thin Pb film and opposing Au surface, we observe no shift in Tc >12 µK down to a minimum spacing of ~70 nm at zero applied magnetic field.

A novel wearable wideband antenna for application in wireless medical communication systems with jeans substrate

In this paper, a novel wearable wideband antenna for application in wireless medical communication systems (0.9–6 GHz) is designed. For bandwidth enhancement, five parallel metal plates (PMPs) are placed on the top of the antenna’s patch without any disturbing effects on the performances. With the help of the proposed method, the bandwidth has been increased by about 3 GHz in comparison with the conventional one. The antenna dimensions are 60 × 48 × 0.8 mm3 or 0.72 × 0.57 × 0.009 λg 3 where λg is the guided wavelength at 2.4 GHz. Simple design, wearable, wide bandwidth, and compact size are the most important benefits of the proposed antenna. Finally, to prove the simulations and designs, the proposed antenna was fabricated. The measurement outcomes are also consistent with the simulation results.

Casimir force between ideal metal plates in a chiral vacuum

We calculate the Casimir force between two parallel ideal metal plates when there is an intervening chiral medium present. Making use of methods of quantum statistical mechanics, we show how the force can be found in a simple and compact way. The expression for the force is in agreement with that obtained recently by Jiang and Wilczek (Phys Rev B 99:125403, 2019), in their case with the use of Green function methods.

Preliminary Study and Numerical Investigation of an Electrostatic Unit for the Removal of Fluoride From Thermal Water of Ethiopian Rift Valley

This article deals with the numerical modeling of the multiphysics investigation of an electric-field-based device for the defluoridation of Ethiopian water to mitigate fluorosis while satisfying the World Health Organization quality requirement for potable water. A tubular reactor with metallic parallel plates, connected to a static voltage source, exerts an electric force on the ion in solution, attracting it to the electrodes. Meanwhile, the ion is drifted by the laminar water flow which, in turn, allows us to separate and collect the F $^{-}$ -rich stream from the potable one. In this system, the electrostatic problem and the mass transport are coupled according to the highly nonlinear modified Poisson–Nernst–Planck–Stokes equations system. Therefore, carefully modeling the dielectric permittivity, the ionic diffusivity, and mobility as function of fluoride concentration and temperature, the set of operating parameters to ensure the highest fluoride removal from Ethiopian thermal water is identified.

Design and coupling characteristics of terahertz dual-core anti-resonant fiber

The THz wave has good photonic and electronic properties, and has high penetration for non-polar materials, but its own photon energy is low. In addition, the THz wave also has characteristics such as wide bandwidth and large communication capacity, thereby making the THz wave possess important academic value and wide application prospects in the fields of non-destructive testing, biomedical imaging and communication. The development of THz technology requires not only high-performance THz waveguide technology for efficient transmission of THz waves, but also important optical devices such as optical switches, modulators, and couplers that are suitable for THz bands. With the in-depth study of THz waveguide technology, researchers have proposed many high-performance THz waveguide structures, such as metal hollow core tube waveguide, parallel metal plate waveguide, photonic crystal fiber and microstructure hollow core fibers, among which hollow-core photonic crystal fibers and hollow-core anti-resonant fibers (HC-ARF) have developed rapidly in recent years. So far, THz single-mode single-polarization fiber and high-birefringence fiber have been widely studied, but the researches on the fiber structure and devices that realize THz wave directional coupling are relatively rare. In this paper, we study the influences of the arrangement and distribution of the inner and outer claddings of HC-ARF on transmission characteristics, and thus design a new type of THz dual-core anti-resonant fiber. Compared with ordinary quartz fiber couplers and dual-core photonic crystal fibers, it can utilize a relatively simple structure and achieve directional coupling above 2 THz. Using the finite element analysis method to theoretically analyze the loss characteristics and coupling characteristics of the fiber, it is found that HC-ARF changes the periodic arrangement and distribution of the inner cladding tube within a certain range, which can achieve mode leakage without affecting the fiber transmission characteristics. So the THz dual-core anti-resonant fiber can be designed by using the mode leakage coupling mechanism. By changing the core distance and core gap size, the directional coupling with a coupling length of 0.72 m is realized at a transmission frequency of 2.5 THz. This terahertz dual-core anti-resonance fiber will have an important application value in terahertz optical devices such as terahertz optical switches, modulators and couplers.

太赫兹平行平板金属波导T型腔中消逝模共振频率的理论分析

太赫兹平行平板金属波导T型腔中消逝模共振频率的理论分析

Examination of Poly (Styrene-Butadiene-Styrene)-Modified Asphalt Performance in Bonding Modified Aggregates Using Parallel Plates Method.

Although asphalt-aggregate bonding provides contacting strength for hot mix asphalt (HMA), it is still ignorant in dynamic shear test, due to the only use of metal parallel plate. Modified parallel plates cored from different types of aggregate were provided to simulate aggregate-asphalt-aggregate (AAA) sandwich in HMA, aiming at the comprehensive interpretation on bonding’s influence. This study began with an experimental design, aggregate plates, and joint clamps were processed to be installed into the rheometer. Aggregate type and loading conditions were set as essential variables. Subsequently, microscopic tests were utilized to obtain chemical components of aggregate, micro morphology of interface, and roughness of plates. The shearing tests for poly (styrene-butadiene-styrene)-modified asphalt were conducted in bonding with aggregate plates. Meanwhile, contrasting groups adopting metal plates followed the same experimental procedures. The results indicate that the influence of aggregate type on binder’s rheological characteristics is dependent on the experimental variables, and microscopic characteristics and component differences should be taken into consideration when selecting aggregates in designing asphalt mixtures.

A 3-D-Printed Wideband Circularly Polarized Parallel-Plate Luneburg Lens Antenna

This communication presents a 3-D-printed wideband parallel-plate circularly polarized Luneburg lens (LL) antenna. The proposed structure of dielectric posts truncated by two metallic parallel plates serves not only as a LL, but also as a wideband linear-to-circular polarizer. The permittivity variation of the LL is realized by positioning dielectric posts with various radius (r) based on the optics theory and the effective medium theory (EMT). On the other hand, the desired circular polarization is realized by exciting two orthogonal propagating modes with different phase constants thanks to the integrated parallel plates. To verify our concept, a prototype was fabricated using 3-D-printing technology. Based on the measurement results, the proposed antenna achieves an overlapped bandwidth of 43% (21–32.5 GHz) in terms of the reflection coefficients lower than −10 dB and the axial ratios smaller than 3 dB. Good agreement between simulation and measurement is obtained.

2D flat Luneburg lens antenna for multibeam scanning application

A two-dimensional (2D) flat Luneburg lens antenna (LLA) operating at Ka-band is presented in this Letter. Based on the transformation optics, the 2D conventional Luneburg lens is compressed to the flat form. The proposed flat LLA is composed of six discretised dielectric layers with different permittivity, two metallic parallel plates and an E-shaped microstrip patch antenna array. By switching on/off the array elements, the lens antenna is able to achieve 1D beam-scanning with a scan coverage of ±30° at 28 GHz. The proposed lens antenna has a low profile of 7 mm, a focus-to-diameter ratio of 0.42, and the simulated/measured aperture efficiency for the on-axis beam is 56.8/36% at 28 GHz. The proposed 2D flat LLA is highly suitable for 5G mm-wave wireless communication with the advantages of low profile, wide beam-scanning range, low cost, and easy fabrication.

Compact Beam-Scanning Flat Array Based on Substrate-Integrated Waveguide

A compact beam-scanning flat antenna array with high gain based on the substrate- integrated waveguide (SIW) is presented in this article. The radiation elements are the continuous transverse stub (CTS) constructed by SIW, which are arrayed on the substrate. The SIW-CTS array has a 4 dB higher gain than the traditional CTS array with the metal parallel plate waveguide and the theoretical explanation is analyzed. A new compact corporate-feed network consisting of an SIW-horn and a flat lens is also proposed. The flat lens could convert the cylindrical wavefront generated by the feed probe and the SIW-horn to a planar wavefront for feeding the CTS array. The Taylor distribution of the feed level made the array has a low sidelobe and high gain. The beam scanning of the array could be realized by simply moving the small SIW-horn along the line across the focal point. An eight-element array is designed, simulated, and fabricated to verify the design. The measured results show that the scanning range is from -35° to 35° with the highest gain of being 20.6 dBi and the sidelobe level of -25.2 dB at the broadside.

2.5-D Miniaturized Multifunctional Active Frequency-Selective Surface

In this paper, a 2.5-D approach has been used to design 2.5-D miniaturized multifunctional active frequency-selective surfaces (2.5-D MMAFSSs). The unitary element, based on the via-connected metal strips and metallic parallel plates, can be miniaturized to 0.063λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> , where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the free-space wavelength. To achieve the relative polarization symmetry, four similar subcells based on the unitary element are combined together to constitute a 2.5-D MMAFSS unit cell. The novelty of the proposed design lies in four independent operating states that can be realized by actively changing the on-off states of p-i-n diodes. In addition, the miniaturized configuration is beneficial for the easy realization of multiple electromagnetic states with great angle stability and polarization insensitivity. For a better understanding of the physical principle, the analyses of both surface current and electric field distributions are conducted at resonance frequencies. Also, the equivalent circuit models are established to further clarify the working mechanism of the structure. Finally, a prototype of the 2.5-D MMAFSS operating at 1.9 GHz is fabricated and measured to validate the proposed concept, and the experimental results are in satisfactory agreement with the simulated ones.

Stable Casimir equilibria and quantum trapping.

The Casimir interaction between two parallel metal plates in close proximity is usually thought of as an attractive interaction. By coating one object with a low-refractive index thin film, we show that the Casimir interaction between two objects of the same material can be reversed at short distances and preserved at long distances so that two objects can remain without contact at a specific distance. With such a stable Casimir equilibrium, we experimentally demonstrate passive Casimir trapping of an object in the vicinity of another at the nanometer scale, without requiring any external energy input. This stable Casimir equilibrium and quantum trapping can be used as a platform for a variety of applications such as contact-free nanomachines, ultrasensitive force sensors, and nanoscale manipulations.

Two-dimensional photonic crystal with ring degeneracy and its topological protected edge states

We propose a two-dimensional photonic crystal that possesses a degenerate ring in the momentum space. The photonic crystal is composed of the parallel-plate metal filled with a periodically arranged square array of metallic cylinders. Opening an air gap breaks the z-inversion symmetry, leading to the modes coupling (bi-anisotropy response) of TE and TM waves. This induced electric-magneto coupling, a similar role of the spin-orbit interaction in the condensed matters, results in a complete topological band gap around the degenerate frequency. The bulk bands below the band gap take non-zero Z2 topological invariant characterized by the evolution of the Berry phase. As a consequence, the interface of two photonic crystals with opposite bi-anisotropy supports topological protected edge states that exhibit one-way propagation and are highly resistant to disorders. Our work might be very useful for the design of topological photonic crystals and may serve as a platform for studying pseudo-spin photonics.

Achieving subwavelength field confinement in sub-terahertz regime by periodic metallo-dielectric waveguides.

In this paper, we report on a periodic metallo-dielectric structure that supports geometry-induced surface plasmons in the sub-terahertz regime. The proposed structure is made up of a dielectric-coated metallic grating sandwiched by parallel metal plates. Based on the modal analysis of 2D and 3D structures, the impact of a metal cladding and a customized dielectric coating on the dispersion relation and field distribution of the guided surface wave is investigated. It is found that modal field confinement is improved in the presence of a metal cladding without narrowing the operational bandwidth of the waveguide. Moreover, a customized subwavelength-sized dielectric coating based on high-resistivity silicon (HR-Si) can further improve the confinement. As a result, by incorporating both the HR-Si coating and the metal cladding in a conventional metallic grating, subwavelength field confinement is achieved over nearly a 2:1 frequency bandwidth. The achieved performance makes the realization of extremely-low radiation loss sharp bends possible. In particular, the achieved radiation loss is less than 0.5dB for a 90° bend of radius λ0/4 based on a waveguide cross-sectional dimension of almost λ0/10 where λ0 is the free-space wavelength at the maximum frequency of operation. The proposed waveguide is promising for the implementation of sub-terahertz guided-wave devices and circuits thanks to its outstanding field confinement and ruggedized and shielded structure.

Capacitor-Inspired Metamaterial Inductors

Capacitors and inductors, those familiar basic circuit elements, have very different shapes and structures: Capacitors are made of parallel metallic plates, while inductors are formed from wound metallic wires. Inspired by $o\phantom{\rule{0}{0ex}}p\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}l$ $m\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}s$ (metamaterial-based nanocircuitry for light), the authors propose a parallel-plate structure filled with a negative-permittivity medium that nevertheless behaves as an inductive circuit element, and may exhibit a higher $Q$ factor than conventional inductors, as well as other advantages. This suggests exciting possibilities in the design of low-loss microwave lumped circuits and electrically small antennas with subwavelength dimensions.

A Simple Method on Transformer Principle for Early Age Hydration Monitoring and Setting Time Determination of Concrete Materials

This paper deals with the development of a low-cost measurement system based on transformer principle with a lossy capacitive load for setting time determination of freshly mixed cement paste. The initial setting time is an important parameter to ensure transporting, placing, and compacting of material to be utilized for the civil structure. Determination of the final setting time helps in removal of a framework after appropriate strength gaining. The proposed method employs a test cell of Vicat instrument with two parallel metal plates. The cement paste behaves as a lossy dielectric kept in the test cell. To determine the setting times, the sample cell was connected to the secondary terminals of a transformer and the primary current was measured at a regular interval of time. The measured primary current was utilized to monitor the possible early age hydration and to determine the initial and final setting time of the different mixture of the cement samples. Results are compared with the results of the conventional Vicat apparatus and are found to be effective for setting time determination. This proposed technique gives privilege for online hydration monitoring of the cement paste and can alternately be used in place of Vicat apparatus.

Electrical Characterization of Human Biological Tissue for Irreversible Electroporation Treatments.

Irreversible electroporation (IRE) is a cancer therapy that uses short, high-voltage electrical pulses to treat tumors. Due to its predominantly non-thermal mechanism and ability to ablate unresectable tumors, IRE has gained popularity in clinical treatments of both liver and pancreatic cancers. Existing computational models use electrical properties of animal tissue that are quantified a priori to predict the area of treatment in three dimensions. However, the changes in the electrical properties of human tissue during IRE treatment are so far unexplored. This work aims to improve models by characterizing the dynamic electrical behavior of human liver and pancreatic tissue. Fresh patient samples of each tissue type, both normal and tumor, were collected and IRE pulses were applied between two parallel metal plates at various voltages. The electrical conductivity was determined from the resistance using simple relations applicable to cylindrical samples. The results indicate that the percent change in conductivity during IRE treatments varies significantly with increasing electric field magnitudes. This percent change versus applied electric field behavior can be fit to a sigmoidal curve, as proposed in prior studies. The generic conductivity data from human patients from this work can be input to computational software using patient-specific geometry, giving clinicians a more accurate and personalized prediction of a given IRE treatment.

Inkjet Printed Parallel Plate Capacitors Using PVP Polymer Dielectric Ink on Flexible Polyimide Substrates.

Inkjet printing (IJP) is an exciting new additive manufacturing technology that promises monolithic electronic circuit fabrication of $\mu \mathrm{m}$ thin low-cost large-area electronic low-cost body-worn flexible sensors. In this work, we demonstrate inkjet printed multilayer metal-dielectric-metal capacitors on flexible polyimide (PI) substrate by formulating a custom dielectric ink based on Poly 4-vinylphenol (PVP). Silver nanoparticle ink was used for printing theconductive parallel metal plates. We also demonstrate control over the capacitance values by varying the design parameters and succeeded in printing capacitors in the range 8.8 pF to 467 pF, with excellent repeatability on flexible PI substrates. A functional LC circuit using these printed capacitors has been designed and demonstrated to have a resonance frequency of 24.3 MHz. These results are a vital step forward towards monolithic printing of flexible electronic circuits using IJP technique formany applications such as body-worn sensors.