Is DC Power Transmitted by Electromagnetic Waves?

The Standard Lattice Model predicts that under high stress, the outer most electrons of the Si-O bonds of a rock get ejected into the lattice's interstitial space. This loosely bound exoelectron cloud will, in a battery's electric field, have a direct current (DC) I; it will also absorb electromagnetic (EM) waves which result in an alternating current (AC) component in the induced current. Both effects have been measured. At high stress just before fracture, the DC current shows a slow rise due to electron tunneling followed by a sudden rise due to the breaking bond electrons. The AC current's voltage amplitude shows a drop as the current increases, and returns to normal after fracture when the current decreases to normal. This is the conservation of energy:absorbed wave energy E=V×I, AC current power. This AC fracture result demonstrates that EM waves can be used to actively probe the changes in highly stressed crust zones.

A mechanically tunable electromagnetic wave harvester and dual-modal detector based on quasi-static van der Waals heterojunction

The increasing need for electrical energy encourages the birth of methods to utilize various forms of energy available in nature called energy harvestin. One of them is from electromagnetic waves that are massif used daily by the community. In this study, a rectifier antenna (rectenna) was created using a 5-stage voltage doubler method with the aim of generating DC electrical energy from the input of electromagnetic waves that propagate freely in the air. Electromagnetic waves are captured using two types of antennas with the aim of capturing different frequencies, namely UHF TV antennas with a working frequency of 470-806 MHz and WiFi antennas with a working frequency of 2400 MHz commonly used by the public. Because testing is conducted in open spaces, where environmental change conditions greatly affect the captured electromagnetic geombang encroachment, DC electrical power tends to change during testing. The largest DC electricity generated by WiFi antenna input is 1,420V and the average voltage is 231.7mV/min with a distance of 90cm from the largest frequency source and UHF TV antenna is 648mV and the average voltage is 478.16mV/min with a distance of 0 cm from the largest frequency source

A transcutaneous energy transmission (TET) system is the most common way to power artificial hearts and ventricular assist devices. However, an external battery used with a TET system poses several problems, such as its heavy mass, small charge capacity, and long recharging time. The battery is indispensable when patients want to be ambulatory. This article proposes a new type of TET system that does not require an external battery because electrical energy is supplied remotely by using electromagnetic waves. For this system to operate, multiple transmitting antennas have to be mounted in a room or facility that has been shielded from electromagnetic waves, and a receiving antenna is attached to the patient. Electromagnetic waves transmit electrical power from the transmitting antennas to the receiving antenna. The received electrical power is sent to an implanted device through the TET system. The total power efficiency was plotted against the transmitter-receiver distance by measuring the power that was input to the transmitting antennas, and the final direct current (DC) power that was received by the receiving antenna. A 430-MHz frequency was applied in the experiments. The obtained efficiency was around 10% within a transmitter-receiver distance of 1 m when Yagi-Uda antennas were used for the transmitting antennas and two other types of antenna were used for the receiving antennas: a folded dipole with a reflector and a single loop with a reflector. The results suggested that the proposed system is worth considering. The proposed system would go a long way toward enhancing the patient's quality of life compared with the currently used conventional TET system.

Electromagnetic shielding properties of epoxy composites with hybrid filler nanocarbon/BaTiO3

Analysis of electromagnetic response of cells and lipid membranes using a model-free method

Programmable metasurface technology can achieve flexible manipulations of electromagnetic waves in real time by adjusting the surface structure and material properties and has shown extraordinary potential in many fields such as wireless communications and the Internet of Things. However, most of the programmable metasurfaces have a common feature: a tail (electrical wires and DC powers), which is difficult to supply in some particular application scenarios such as canyons and mountains. To eliminate the limitation of DC power supply, the programmable metasurface and wireless power transfer technology are combined to propose a tailless information-energy metasurface (IEMS). The tailless IEMS platform can dynamically control electromagnetic waves without relying on an external DC power supply; instead, the required DC power is provided internally by the IEMS platform itself. In the tailless IEMS experiments, the concept is demonstrated through the dynamic regulation of wireless channels and the wireless transmission of DC power. This work provides a self-powered method for programmable metasurfaces, expands the application scenarios, facilitates the miniaturization of systems, and makes it easy to integrate with other systems.

We study for the first time the interaction between the waveguide modes of graphene structure and freely propagating terahertz (THz) electromagnetic waves (this interaction takes place within the light cone). We revealed a new and rather unexpected physical phenomenon by showing that freely incident THz electromagnetic waves can resonate with the surface transverse electric (TE) modes of the graphene waveguide in virtue of these modes having their dispersions in the vicinity of the light cone. The dispersion and amplification of surface TE modes in a dielectric waveguide covered with two graphene layers biased by direct current (DC), as well the amplification and lasing of incident THz wave by excitation of TE mode resonances, are investigated. The DC flows perpendicular to the direction of the surface wave propagation and creates the capacitive complex conductivity of graphene at THz frequencies, which is necessary for the existence of surface TE modes in graphene. The real part of graphene conductivity can be negative at THz frequencies due to DC in graphene which leads to amplification and lasing of THz radiation. Such structure can be of great practical importance because an external THz wave can be amplified or generated in lasing process without using special coupling elements commonly needed for ensuring the interaction between external THz wave and surface waveguide modes. The use of a two-layer graphene structure makes it possible to reduce the charge–carrier drift velocity required for reaching the lasing threshold at those resonances, as compared to a structure with a single graphene layer.

Rectenna is the key component in radio-frequency circuits for receiving and converting electromagnetic waves into direct current. However, it is very challenging for the conventional semiconductor diode switches to rectify high-frequency signals for 6G telecommunication (>100 GHz), medical detection (>THz), and rectenna solar cells (optical frequencies). Such a major challenge can be resolved by replacing the conventional semiconductor diodes with tunneling diodes as the rectenna switches. In this work, metal-insulator-metal (MIM) tunneling diodes based on 2D insulating materials were designed, and their performance was evaluated using a comprehensive simulation approach which includes a density-function theory simulation of 2D insulator materials, the modeling of the electrical characteristics of tunneling diodes, and circuit simulation for rectifiers. It is found that novel 2D insulators such as monolayer TiO2 can be obtained by oxidizing sulfur-metal layered materials. The MIM diodes based on such insulators exhibit fast tunneling and excellent current rectifying properties. Such tunneling diodes effectively convert the received high-frequency electromagnetic waves into direct current.

The electromagnetic wave impinging on the spatially modulated two-dimensional electron liquid (2DEL) induces a direct current (DC) when the wave amplitude modulated with the same wave vector as the 2DEL but is shifted in phase (the ratchet effect). The recent theory of this phenomenon predicted a dramatic enhancement at the plasmonic resonances and a non-trivial polarization dependence [1]. We will present the results of the numerical simulations using a hydrodynamic model exploring the helicity dependence of the DC current for silicon, InGaAs, and GaN metamaterial structures at cryogenic and room temperatures. In particular we will report on the effect of the DEL viscosity and explore the nonlinear effects at large amplitudes of the helical electromagnetic radiation impinging on the ratchet structures. We will then discuss the applications of the ratchet effect for terahertz metamaterials in order to realize ultra-sensitive terahertz (THz) radiation detectors, modulators, phase shifters, and delay lines with cross sections matching the terahertz wavelength and capable of determining the electromagnetic wave polarization and helicity. To this end, we propose and analyze the four contact ratchet devices capable of registering the two perpendicular components of the electric currents induced by the elliptically or circularly polarized radiation and analyze the load impedance effects in the structures optimized for the ratchet metamaterial THz components. The analysis is based on the hydrodynamic model suitable for the multi-gated semiconductor structures, coupled self-consistently with Poisson’s equation for the electric potential. The model accounts for the effects of pressure gradients and 2DEL viscosity. Our numerical solutions are applicable to the wide ranges of electron mobility and terahertz power. [1] I. V. Rozhansky, V. Yu. Kachorovskii, and M. S. Shur, Helicity-Driven Ratchet Effect Enhanced by Plasmons, Phys. Rev. Lett. 114, 246601, 15 June 2015

Summary form only given. When returning to the Earth, the spacecrafts enter the upper atmospheric layers with a hypersonic speed. In this case, the shock heated air around them becomes weakly ionized. The gas ionization behind the shock front is associative in nature and occurs through chemical reactions between fragments of molecules. The formation of a plasma layer near the surfaces of spacecraft causes serious problems related to the blocking of communication channels with the Earth and other spacecraft. A promising way of restoring the radio communications is the application of electrical and magnetic fields for controlling the plasma layer parameters. Sheaths with an almost zero electron density and a high ion density are known to be formed near a surface when an ac or dc gas discharge is ignited in a plasma. Since the electromagnetic waves interact mainly with the plasma electron component, a decrease in electron density ensures the passage of the electromagnetic waves through the plasma sheath. In this work, we consider the combined action of a direct current (DC) discharge and a magnetic field on the plasma flow near a flat surface at a low gas pressure. Our simulations ar e performed using a two dimensional Particle in cell method (PIC MCC). The kinetics of electrons in nitrogen includes elastic collisions, the excitation of rotational, vibrational, and meta stable levels, and ionization. Based on two dimensional kinetic PIC MCC simulations, we considered the possibility of locally controlling the plasma sheath parameters near a flat surface i n a hypersonic flow. We showed that the combined action of D C discharge, a constant voltage, and a magnetic field on the plasma sheath allows the local electron density to be reduced manyfold. We did not consider the effect of gas flow acceleration during the momentum transfer from ions to gas molecules under resonant charge exchange. The gas flow velocity distribution is specified by a model function.

In this paper, terahertz (THz) characteristics of a direct current (DC) arc discharge uniform plasma are analyzed, which is of practical significance in plasma diagnostics with electromagnetic waves. A model for estimating total collision frequency of DC arc discharge plasma is built based on the Coulomb model and elastic scattering model. Explicit expressions for attenuation coefficient and transmission coefficient of THz wave propagating through a uniform plasma are obtained, which are expressed as a function of plasma frequency and collision frequency in the DC arc discharge. Detailed numerical analysis and discussions are conducted to reveal the influence of electron density, collision frequency, thickness of the plasma, and incident angle of the wave on the transmission characteristics of THz wave in plasma. Results show that the greater are the electron density, collision frequency and transmission length of a wave propagating in plasma, more power of the wave is attenuated. The attenuation energy of laser under horizontal sending and horizontal receiving (HH) polarity is as same as the vertical sending and vertical receiving (VV) polarity in underdense plasma.

Insulated gate bipolar transistors (IGBT) are used broadly in DC power transmission, power converters, and drives. These applications are cost-sensitive and require high module reliability. Researchers have been found that IGBT degradation over time is directly dependent on its junction temperature. Normally the temperature is measured with a temperature sensor close to the IGBT case or module. This requires the predesigning of the converter or results in a cost-effective and inconvenient process. In this paper, we are proposing a non-invasive method of junction temperature extraction, which do not suffer from the difficulties mentioned above. The method is based on the analysis of electromagnetic radiation (EMR) generated by the IGBT. It has been found that the radiation is a function of switching delay of the IGBT, and this delay is directly proportional to the junction temperature. Thus the junction temperature of IGBT is extracted from the EMR. The method requires only a single loop antenna to capture the radiation. Experimentally to increase the junction temperature of IGBT, an accelerated aging method is adopted. Then the junction temperature, the delay time, and the electromagnetic radiations are measured. The junction temperature is extracted from the inverse relation of these three parameters.

Programmable metasurfaces have the real-time programmability for controlling electromagnetic (EM) waves, possessing many potential applications. Programmable metasurfaces were constructed typically by using the direct-current (DC) control system. However, these electronically-controlled metasurfaces need field-programmable gate arrays, power supplies and many wires. In this paper, we present an optically driven programmable microwave metasurface to implement different EM functions, such as dynamic vortex-beam generation and illusion. Our realized optically driven metasurface avoids the cross-talk between the DC signal and EM signal, and can realize noncontact remote control.

In RF energy harvesting, the energy received from electromagnetic waves is converted into useful dc power. The paper aims to review the present strategies for analyzing power conversion efficiency. Several parameters are needed to be evaluated for the power conversion efficiency measurement. Based on the types of functional units, different strategies are analyzed. This review suggests that the gain of the receiver antenna plays a critical role in the RF energy harvesting system. The power conversion efficiency (PCE) has been obtained in RF harvesting systems is ranging from 20% to 82.3%. The overall PCE depends on efficiency of each block.