Input Electric Field Research Articles

Design and analysis of flexible tilt mirror driven by piezoelectric thin sheet actuators

Optical tilt mirrors (OTM) enable the mirrors to achieve high precision posture adjustment, playing a significant role in various optical system applications in the fields such as active optics, adaptive optics, satellite communications and biomedicines. However, the rapid development of modern technologies has brought new challenges to OTM in terms of their dimension, operating space and dynamic performance. Herein, a novel biaxial optical flexible tilt mirror (OFTM) driven by four simple bonded-type thin sheet piezoelectric actuators was proposed, where the OFTM was designed based on the flexible bending motions of composite piezoelectric beams. Particularly, OFTM is mainly composed of PZT sheet and stainless steel substrate, and shows a dimension of 42 mm × 42 mm × 0.2 mm. A theoretical model of OFTM was established to accurately describe the relationship between input electric field and output pose based on elastic beam theory, where the relationship was verified by both finite element analysis and experimental results. Finally, an OFTM prototype was fabricated and presented good performance on motion behaviors. Compared with traditional fast steering mirror (FSM) and MEMS mirror, the developed OFTM shows low cost, small size and simple manufacturing process, which greatly extends the applications of OFTTM in emerging fields.

A high-performance magnetoelectric non-volatile light-emitting memory device

A novel magnetoelectric light-emitting memory (LEM) device that can control the output light intensity and electrical signal based on the input magnetic and electric field strengths has been proposed and demonstrated.

Measurement of low-frequency electric field waveform by Rydberg atom-based sensor

The high polarizability of Rydberg atoms enables the multi-parameters measurement of electromagnetic fields. In this paper, we report on an atomic antenna based on Rydberg atoms in a room temperature vapor cell. The EIT is a destructive interference spectroscopy with a narrow linewidth and can be used to detect small electric fields through Autler-Townes splitting or Stark shifts. In our experiments, we employ cascade-type two-photon excitation electromagnetically induced transparency (EIT) spectroscopy to measure the shift of the Rydberg energy level. We introduce a low-frequency electric field (~kHz frequency) using a built-in electrode technique in the cesium cell. The interaction between the Rydberg atom and electric field induces the Stark shifts, where the amplitude of the electric field is converted into corresponding two-photon detuning by the EIT effect. Furthermore, the amplitude of the low-frequency electric field is converted into an intensity signal of EIT probe beam. Under weak field conditions, it is an approximate linear relationship between EIT transmission signal and input electric field amplitude, enabling measurement of waveform, amplitude, and frequency. We have demonstrated optical measurements of low-frequency electric field using Rydberg atoms. By increasing the power of probe beam and coupling beam, the EIT can increase the response bandwidth from ~MHz to hundreds of MHz. This provides a scalable approach for measuring high-frequency electric fields.

Computational simulations of spatio—temporal plasma dynamics in a very high frequency capacitively coupled reactor

Abstract The standing wave effect in Very High Frequency Capacitively Coupled Plasma (VHF CCP) reactors is a major cause of plasma non-uniformity. The nonlinearly excited higher harmonics exacerbate this non-uniformity. In this work we analyze the physical mechanisms of plasma—electromagnetic wave coupling in detail for a single RF cycle of the input electric field. We consider a simplified CCP reactor geometry operated at 100 mTorr and computationally simulate three cases where the bulk electron density increases from order 1015 m−3 to 1017 m−3. We see the appearance of higher harmonics in the B-dot signal with increasing bulk electron density in accordance with recent experimental measurements. By looking at the spatio-temporal variations of different quantities at a periodic steady state, we observe significant changes in the dynamics of current flow, electromagnetic power deposition and ionization rates within the reactor. In particular, as the electron density increases, we see that the current profile in the bulk plasma exhibits a re-circulation pattern that is correlated with the appearance of structural features in the B-dot signal seen in the measurements.

The efficiency of the electro-osmosis method on the consolidation and strength properties of the gray clay of Tabriz

BackgroundConsolidation of clays could be a very time-consuming procedure. However, preloading can increase the speed of consolidation; applying an electric field can accelerate this procedure significantly. The efficiency of the electroosmosis approach has been studied for different types of clays previously. At the same time, there is no information about the performance of the EO method for Tabriz gray clay.MethodsThis paper investigates the effects of the EO technology on Tabriz gray clay using a modified oedometer consolidation apparatus. The achieved results of the EO consolidation of the Gray clay of Tabriz are compared with the standard Kaolin clay (KC-which produced industrially). Three different electrodes (Iron, Copper, and Aluminum) are employed to study about effects of the electrode type, and two different voltages (12 V and 24 V) are applied to assess the impact of the input electric field on the settlement of samples.ResultsIt is shown that the copper electrode leads to maximum volumetric strains while the iron electrode results in minimum volumetric strains. In addition, it is shown that the larger input voltage leads to larger settlements. The results indicate that the EO approach is more efficient for the Gray clay of Tabriz in comparison to the KC, where gray clay shows larger settlements while subjected to an electric field. Unconfined compression tests are also applied to some samples, and the EO method’s influence on the samples’ strength is discussed.ConclusionsThe achieved results demonstrated that the EO method can be efficiently used to improve the consolidation and strength properties of the gray clay of Tabriz.

Improvement of Power Recovery by Applying a Multi-Pulse Electric Field in the Thermoelectric Cycle Power Generation Process with Pyroelectric Materials

Nanogenerator energy harvesting technologies that transform thermal energies into electricity may help address the growing need for green power. Therefore, this research aims to increase power generation by combining waste heat with pyroelectric nanogenerators as a sustainable energy source. Under optimal conditions, an external multi-pulse electric field can be utilized to generate power using thermoelectric cycle power generation. The greatest power may be gathered by applying various pulses of the external electric field at temperature changes on the surface of the pyroelectric materials. To generate pyroelectric power, a C9 BZT sample was used, and the lowest temperature difference for accomplishing this was 20 °C, with all measurements made on a sample with a lower limit of 120 °C. The maximum generation density was 0.104 mJ/cm2°CkV for a pulse width of 10 ms and 20 pulses of a low voltage (250 V/mm) input electric field. A multi-pulse electric field with low input voltage increases the power generation performance ratio (η) with the pulse count. At the largest number of pulses, the greatest η value for 250 V/mm was 7.834. Finally, it was determined that the developed pyroelectric power generation system may be more effective if a low-voltage, multi-pulse electric field is used.

Differential Structure to Improve Performance of DC Electric Field Sensors

The electric field is an essential electromagnetic environmental parameter in designing and constructing high-voltage direct-current (HVDC) transmission lines. In this paper, a differential structure is proposed to improve the performance of the field mill sensor. Two groups of vanes with the same characteristics generate induced currents with opposite phases, and the difference operation calculates the ground electric field. We calculated the charges and induced currents and optimized the number of vanes of the sensing electrode using the simulation model. Then we designed the I/V circuit and amplifier based on the differential structure and conducted circuit simulation and sensor calibration experiments. Compared with the single input electric field sensor, the noise of the sensor with the differential structure is significantly reduced, and the sensitivity reaches 0.085 V/(kV/m). The results indicate that the field mill sensor with improved differential structure enhances the anti-interference ability and sensitivity.

Impedance Well Effect From Circuit Analysis and New Design Concepts for Ultrabroadband Passive Absorber

The limitation in enhancing the absorption bandwidth of a microwave absorber with a thin thickness in the ultrahigh-frequency (UHF) band has become an important challenge in the electromagnetic scattering field. Therefore, in this study, a new design concept of a single-layer impedance-well (IW) passive absorber is put forward for the first time, which exhibits enhanced absorption bandwidth and effectively approaches the Rozanov thickness limit for passive absorbers. The design concept proposed in this study is explained by using the transmission line theory and circuit analysis. Furthermore, the input impedance and electric field distribution of the IW absorber are systematically analyzed to demonstrate the existence of the IW effect and the predicted functionalities of the IW absorber. The simulated and measured results reveal that the designed absorber with the IW effect can obtain an absorption band over 0.45–2.34 GHz range with a bandwidth ratio (BWR) of 5.2 (135.5%) at a minimum reflectivity reduction of −10 dB under normal incidence. In addition, the thickness is reduced to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.069 \lambda _{{\mathrm {L}}}$ </tex-math></inline-formula> , which <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{{\mathrm {L}}}$ </tex-math></inline-formula> is the wavelength at the lowest operating frequency.

Modeling and Characterizing Two Dielectric Elastomer Folding Actuators for Origami-Inspired Robot

Origami-inspired robots are automated machines that achieve deformation and function through folding. This letter models and characterizes two dielectric elastomer folding actuators, and proposes a new method for driving origami-inspired robots. Multilayer bending dielectric elastomer actuators (MBDEAs) and minimum energy structural dielectric elastomer actuators (MESDEAs) are placed at the creases to drive a rigid origami-inspired robot joint. We establish an analytical model of MBDEAs based on beam bending theory. This model establishes the relationships between the deformation angle and output moment of the MBDEA and the input electric field intensity according to the design parameters. In addition, a design model of MESDEAs with the rectangular hollow area is presented for the equilibrium deformation angle and maximum output moment. The analytical model of MBDEAs for the deformation angle and the design model of MESDEAs are both preliminarily verified by experiments. Finally, we realize the drive of the joint based on MBDEAs and MESDEAs. The design and model are evaluated through experiments. This work paves the way for subsequent motion control of origami-inspired robots and further expands the application fields of dielectric elastomer actuators (DEAs).

Modeling and analysis of an electro-magneto-elastic rotating cylindrical tube actuator

This paper presents the static modeling and analysis of a novel cylindrical tube actuator subjected to a rotation about longitudinal axis with an internally applied air pressure under an electromagnetic field. The current tube actuator belongs to a smart actuator category and is made of an electro-magneto-active polymer filled with a particular volume fraction of suitable fillers. A continuum mechanics-based electro-magneto-mechanical model is developed to predict the response of the actuator for a combined pressure and electromagnetic field loading. To validate the same, the model is compared with the outputs of an existing spring roll actuator. Parametric studies are subsequently performed for varying input pressure, electric field, magnetic field, fillers content, and actuator’s rotational speed. The output sensitivity in terms of strain intensity at inner and outer surfaces of the actuator is also checked at different controlling inputs. In addition, various electro-magneto-mechanical instability curves are drawn to examine the critical inflation of the tube actuator. In general, the developed model provides initial steps toward the modern actuator designs for applications where a precise control with high load-carrying capability of the actuator plays a significant role.

Dynamic Range Enhancement Via Linearized Output in Nanoelectromechanical Systems by Combining High-Order Harmonics

There is a strong non-linearity between the field-emission current amplitude and field intensity. This nonlinearity degrades the dynamic range of digital signal processing in a mechanical oscillator composed of a cantilever. To solve this issue, we propose a linearization method by combining the harmonics of the field-emission current. The proposed method significantly increases the dynamic range. The nonlinearity error is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8.94\times 10^{-3}$ </tex-math></inline-formula> %FS for the proposed method, whereas it is 14.1%FS for the conventional method given by the 2nd harmonic current detection. In addition, the proposed method enables to rake up energy of the higher-order harmonics by utilizing our design framework for combining weights, thereby providing a constant derivative of the output current of the input electric field.

Monodisperse semiconducting poly(N-methylaniline) microspheres and their electrorheological response

Monodisperse semiconducting poly(N-methylaniline) (PNMA) microspheres with a suitable electrical conductivity were fabricated using a chemical oxidation process and employed in an electrorheological (ER) suspension. Morphological image of the synthesized PNMA microsphere was assessed via scanning electron microscope and transmission electron microscope. Its chemical composition and thermal behavior were determined using Fourier-transform infrared and thermal gravimetric analysis, respectively. Chain-like structure formation under an input electric field in ER fluid containing silicone oil and 10 wt% PNMA microspheres was observed directly with optical microscopy. Viscoelastic characteristics of the ER fluid under an input electric field were evaluated with a rotational rheometer. Yield stress with a power exponent of 1.5 was observed, along with typical solid-like property under electric field. Dielectric behavior of the ER suspension measured was also found to be closely associated with its ER behavior.

Computation of Lightning Current from Electric Field Based on Laplace Transform and Deconvolution Method

A method for computation of the lightning channel base current from the corresponding vertical component of lightning electric field was presented. The algorithm was developed by applying Laplace transform. The lightning current was estimated from its deconvolution with a special transfer function. The transfer function includes information about geometry and physical properties of entire lightning impulse generation system. The method was verified for a Heidler-type base current and a MTLL model of its propagation within the lightning channel. Research was done for close, middle, and far distance to the lightning strike point. Optimum performance was obtained for the middle distance of several kilometers where the electrostatic, induction, and radiation components of the transfer function were of the same range. An analysis was done for input electric field with and without noise superimposed on its time domain waveform. Relative uncertainties for the electric field and calculated lightning channel base current were similar each other. The presented approach can substantially increase a number of lightning current parameters which can be identified on the basis of its electric field signature. This method can be applied by the lightning location systems using preprocessing which increases the timing efficiency of the transfer function estimation.

An Integrated Design and Fabrication Strategy for Planar Soft Dielectric Elastomer Actuators

Dielectric elastomers (DEs) are promising soft actuators for use in soft material robots, due to their considerable voltage-induced strain. The actuator's behavior is highly nonlinear due to the complex interplay between the DE, the support structure, and the input electric field, making it a big challenge to automatically design dielectric elastomer actuators (DEAs). Here, in this article, we present an integrated design strategy for planar DEAs, aiming to realize their full potential. To endow the actuator module with the maximal actuation strain, we carry out dimensionless analysis to identify the key design variables, develop a fast finite element analysis model, and thoroughly investigate how the geometric structuring and the material prestretch tailor the voltage-induced deformation. We also provide a fabrication strategy by patterning the compliant electrodes on the DE membrane and then directly printing the support structure made of thermoplastic polyurethane. The experiments show that the optimized actuator obtains a remarkable nominal strain up to 38.6%. We also characterize the dynamic performance of the optimized actuator, evaluate its energy density and power density, and develop a soft locomotion robot that can crawl through a confined tunnel, at a fast moving speed up to 0.17 body length/s.

Synthesis and Electrorheological Response of Graphene Oxide/Polydiphenylamine Microsheet Composite Particles.

Conducting graphene oxide/polydiphenylamine (GO/PDPA) microsheet nanocomposite particles were fabricated via in-situ oxidative polymerization using diphenylamine in the presence of GO. The morphological structures and dimensions of the fabricated GO/PDPA composites were evaluated using transmission electron microscopy and scanning electron microscopy. Electrorheological (ER) responses and creep behaviors of an ER fluid consisting of the GO/PDPA composites when suspended in silicone oil were evaluated using a rotational rheometer under input electric field. Three different types of yield stresses were examined along with dielectric analysis, demonstrating their actively tunable ER behaviors.

A preliminary study on mist CVD-derived ferroelectric Hf1−xZrxO2 films featuring its possibility of suitable operation for non-volatile analog memory

We have newly developed mist CVD-derived Hf1−xZrxO2 films and investigated their physical properties and basic electrical properties for application to ferroelectric analog memory device such as synaptic device for neuromorphic system. It is observed that the films consisted of microcrystal grain including ferroelectric orthorhombic phase by AFM and GIXRD measurements. Both HfO2 and ZrO2 film with 20 nm thickness showed good fatigue endurance against 109 counts of imposed pulse cycling, where some wakeup phenomena were observed. For a range of electric field (up to 1.5 MV cm−1) as memory-writing input with condition of minor ferroelectric hysteresis loop, a linear relationship between the input and resultant polarization at zero electric field, P(E = 0), was obtained. Finally, it is suggested that those films of HfO2, Hf0.55Zr0.45O2 and ZrO2 are basically applicable for the ferroelectric analog memory device. Further investigation is needed in view of degradation against the input electric field and imposed fatigue pulse.

Tunable Electromechanical Liquid Crystal Elastomer Actuators

Liquid crystal elastomers (LCE) are soft materials which anisotropically shape morph in response to external stimuli. Herein, a method to produce large‐area carbon nanotube–LCE nanocomposite films with exceptional electrostrictive properties is examined. A methodology to produce telechelic precursor oligomeric composites at scale (&gt;100 g) is presented along with the continuous casting and photocuring process. The carbon nanotubes are well‐aligned and well‐dispersed in the films, which exhibit exceptional anisotropic thermomechanical, optical, and thermal shape change characteristics. When an electric field is applied through the film thickness, the material quickly and reversibly contracts along the alignment direction. As an example, a compliant carbon nanotube–LCE film contracts &gt;4% against a 140 kPa load, roughly comparable to the blocking force of many natural muscular tissues. Furthermore, it is demonstrated that this tunable contraction is dependent upon the electric field strength, and that the contraction mimics the form function of the input electric field (e.g., a sine wave). These compliant actuators are excellent candidates for incorporation into soft and/or biological systems.

Determination of the electric field and its Hilbert transform in femtosecond electro-optic sampling

We demonstrate time-domain sampling of mid-infrared electric field transients and their conjugate counterparts exploiting the dynamical Pockels effect. To this end, the complete polarization change of few-femtosecond probe pulses is studied. An intuitive picture based on a phasor representation is established before gaining quantitative understanding in experiment and theory. In the standard version of electro-optic sampling, the electric field is determined by analyzing the change of ellipticity of the probe polarization. Beyond this, we find that a temporal gradient of the input electric field manifests itself in a rotation of the polarization ellipsoid of the probe. The relative contribution of sum- and difference-frequency mixing processes and their spectral distribution over the near-infrared probe bandwidth are identified as key aspects. If one of these processes dominates, detecting ellipticity changes and polarization rotation as a function of time delay results in two wave forms which are Hilbert transforms of each other. Such conditions may be achieved by angle phase matching in birefringent materials or spectral filtering of the probe after the nonlinear interaction. In this case, a static phase introduced by birefringence or reflection at metallic mirrors results in a specific phase shift of both time traces with respect to the input electric field. Contributions from sum- and difference-frequency generation are found to be equivalent when using electro-optic sensors with isotropic refractive index. Polarization rotations in the low- and high-frequency parts of the probe then tend to cancel out. In this limit, spurious additional phase shifts do not change the phase of the detected transients. This fact leads to a robust recovery of the carrier-envelope phase of the input wave form. Clarifying the role of imperfections of superachromatic phase retarders completes our survey on proper determination of the electric field and its conjugate variable.

A New Compact Quad-Band Metamaterial Absorber Using Interlaced I/Square Resonators: Design, Fabrication, and Characterization

This paper presents the design and analysis of a new compact quad-band metamaterial absorber (MMA). The proposed structure is constructed as an array of 12 × 13 unit cells, each one is based on a combination of interlaced I/square resonators supporting four distinct resonant frequencies. The proposed metamaterial unit cell is printed on FR-4 substrate with thickness 1.5 mm and size 20 mm × 20 mm. The MMA structure exhibits four distinct absorption peaks at 2.248, 2.878, 4.3 and 5.872 GHz with absorption rates of 96, 93, 93, and 95 %, respectively, under normal incidence. This design achieves a negative permittivity and permeability that is applicable for S-band and C-band operating frequencies. The MMA unit cell structure has a 3-dB bandwidth of 78, 89, 144 and 202.6 MHz. The proposed structure has compactness of 0.15 λ0× 0.15 λ0 with thickness of 0.0112 λο, where λ0 is the free-space wavelength with respect to the lowest resonance frequency (2.248 GHz). The input impedance, surface currents and electric field distributions are shown to illustrate the mechanism of the structure. The design has been fabricated showing a good agreement between simulated and measured results. The proposed absorber structure can be used in different applications such as electro-magnetic protections, as well as military and medical applications. All simulation results are performed using the Computer Simulation Technology (CST), Microwave Studio 2018 software and Mathwork simulation tool MATLAB ver. 2011.

Study of electric fields of diffraction from spatial light modulator: discussion.

A complete study of electric field vectors and efficiencies of diffraction orders for a phase pattern addressed to a pixelated spatial light modulator (SLM) is discussed here. General mathematical expressions of electric field vectors from SLM are explored here analytically for an arbitrary pattern on SLM with a given input electric field. Using the general expression, we calculate orientations of the electric fields of diffraction for sinusoidal and binary patterns of varying duty cycles. The patterns result in diffracted beams of various orders with different efficiencies calculated analytically and matching well with the experimental results. The binary pattern with 50% duty cycle delivers significant distribution of energies where all the even orders are absent, and the diffraction efficiency of the first-order beam can be close to 40% using an appropriately chosen modulation depth. Using the general expression, it is possible to obtain fields and efficiencies of diffraction for any arbitrary pattern on SLM. The discussion might help researchers using SLM in standard optics experiments.