Electric Field Strength Measurements Research Articles

Key comparisons CCEM.RF-K-20 in the area of electric field strength measurements

The method of calibration of a portable standard on equipment of the state standard GET 45-94 for electric field strength is presented. Analysis of the results of key comparisons CCEM.RF-K-20 is provided.

On the use of relative line intensities of forbidden and allowed components of several HeI lines for electric field measurements

Abstract In this Letter we propose a method for electric field measurements based on intensity ratio of forbidden and allowed helium lines. HeI 402.6 nm, HeI 447.1 nm, and HeI 492.1 lines and their forbidden components are used for the measurement of electric field strength in the cathode region of the abnormal glow discharge in helium–hydrogen mixture. Electric filed strength was independently determined using polarization spectroscopy of H β line and then compared with electric filed strength obtained from relative intensity of HeI forbidden and allowed lines.

An active antenna for measuring pulsed electric fields

The feasibility of creating an ultra-wideband receiving antenna comprising a dipole loaded on an active element based on field-effect transistors is analyzed. The antenna is intended for registration of waveforms and measurement of instantaneous electric field strengths for electromagnetic radiation pulses of nanosecond and subnanosecond durations.

The effects of electric fields on charged molecules and particles in individual microenvironments

Measurements of small air ion concentrations, electrostatic potential and AC electric field strengths were taken in an office setting to investigate the link between electric fields and charged molecule and particle concentrations in individual microenvironments. The results obtained indicate that the electromagnetic environments individuals can be exposed to whilst indoors can often bear little resemblance to those experienced outdoors in nature, and that many individuals may spend large periods of their time in “Faraday cage”-like conditions exposed to inappropriate levels and types of electric fields that can reduce localised concentrations of biologically essential and microbiocidal small air ions. Such conditions may escalate their risk of infection from airborne contaminants, including microbes, whilst increasing localised surface contamination. The degree of “electro-pollution” that individuals are exposed to was shown to be influenced by the type of microenvironment they occupy, with it being possible for very different types of microenvironment to exist within the same room. It is suggested that adopting suitable electromagnetic hygiene/productivity guidelines that seek to replicate the beneficial effects created by natural environments may greatly mitigate such problems.

ＳＦＮ環境下における長距離遅延プロファイル測定装置の開発

This paper describes an evolutional long delay wave measuring apparatus for measuring delay profiles and levels accurately in the single frequency network (SFN) used for terrestrial digital TV broadcasting.Measurable delay times using the conventional scattered pilot (SP) signal method are theoretically restricted to less than 0.5ms.This equipment has no limit to the length of delay times it can measure. We fabricated and tested a proto type and confirmed that it can be used to measure delay profiles with delay times longer than 1ms.In addition, we discuss errors that occurred when using this method and the countermeasures that were taken.Performance was satisfactory. In the future, this apparatus will be effective for achieving coverage with excellent quality following the construction of a new relay station that will expand SFN. In addition,it will be effective for electric field strength measurements taken during maintenance and it will assist in the efficient operation of SFN by its ability to confirm the quality of coverage.

Reply to comments on ‘Intensity ratio of spectral bands of nitrogen as a measure of electric field strength in plasmas’

It is argued that the experimental results presented by Paris et al in J. Phys. D: Appl. Phys. (2005) 38 3894 are correct. It is shown that there is no evidence of filamentation or local electric field reinforcement in discharge. It is discussed that reaction scheme and rate constants for deactivation of excited nitrogen ion proposed by Pancheshnyi in his Comment must be specified for conditions corresponding to the experiment carried out by Paris et al.

Comments on ‘Intensity ratio of spectral bands of nitrogen as a measure of electric field strength in plasmas’

It is pointed out that an extra process must be taken into account for a correct interpretation of the experimental measurements reported by Paris et al (2005 J. Phys. D: Appl. Phys. 38 3894). The analysis presented here allows partial use of the results of the above-mentioned paper with some limitations.

Intensity ratio of spectral bands of nitrogen as a measure of electric field strength in plasmas

The ratios of intensities of the spectral bands of molecular nitrogen corresponding to transitions ), N2(C 3Πu, v = 0) → N2(B 3Πg, v = 0) and N2(C 3Πu, v = 2) → N2(B 3Πg, v = 5) as a function of the applied electric field strength were measured for air in the pressure range of 300 to 105 Pa. The non-self-sustaining dc discharge in a parallel-plane gap was used for excitation of gas molecules. The reduced field strength was varied in the range of (150–5000) × 10−21 V m2. The measured ratio of intensities as a function of electric field strength is compared with the theoretical estimates made by other authors. The obtained intensity ratio versus field strength curves can be used for field strength estimation in plasmas if the nitrogen molecules are excited dominantly from the ground state directly by the electron impact.

Experimental and theoretical investigations of a low-pressure He–Xe discharge for lighting purpose

Low-pressure cylindrical dc glow discharges in a mixture of helium and 2% xenon are studied by experiment and self-consistent modeling. They can be used for the design of mercury-free vacuum ultraviolet sources and fluorescent lamps for publicity lighting. Experimental diagnostics of the column plasma includes measurements of the axial electric field strength and of the axis densities of the four lowest excited states of xenon. The electric field is determined from probe measurements. The particle densities are derived from the results of tunable diode laser absorption spectroscopy. Experimental investigations are assisted by a self-consistent analysis of the dc positive column plasma. A comparison between calculated and measured values of the axial electric field strength and the densities of excited xenon atoms is presented and discussed. The validated model is used for optimization of the discharge conditions by variation of the discharge current, gas pressure, and tube radius with respect to the radiation power and efficiency of the 147 nm resonance line of xenon. The discussion includes an analysis of the power budget of the column plasma.

Power bus signal integrity improvement and emi mitigation on multilayer high-speed digital pcbs with embedded capacitance

The continuous technology trend in the telecommunication market toward higher operating frequencies and high processing performances will give rise to new sophisticated chip sets, processors, and RF transceivers which will demand new feature to the PCB designs. As the complexity of the integrated circuits increases, signal integrity (SI) and electromagnetic compatibility (EMC) become key elements in the board design process. This paper analyzes the beneficial effects that a thin dielectric material between a pair of power and ground layers (embedded capacitance) has both in reducing power bus resonance amplitudes (SI approach) and radiated emissions (EMC approach) as well. Scattering parameter measurements carried out on the power bus of two production boards are presented and correlated with the electric field strength measurements conducted on the same boards in a semianechoic chamber.

Macrocell electric field strength prediction model based upon artificial neural networks

A new macrocell prediction model for mobile radio environment is presented. The use of feedforward artificial neural networks makes it possible to overcome some important disadvantages of previous prediction models, including both deterministic and statistical types. Our sample implementation is based upon extensive electric field strength measurements (in the 900-MHz frequency band) that were carried out in the city of Belgrade using six different test transmitter locations. Comparison between the data obtained by the proposed electric field strength prediction model and independent measurement sets show that the proposed model is sufficiently accurate for use in planning mobile radio systems.

Vibrating-wire transducers for electrostatic measurements

This paper describes new kinds of electric fieldmeters having vibrating-wire transducers. The first main characteristic which distinguishes these devices from traditional vibrating sensors is location of sensing electrodes and modulator outside of the transducer casing. The second is the considerably enlarged area of electric field transformation. Due to these features the sensitivity of vibrating-wire fieldmeters is comparable to field mills. Complete enclosure of these meters, in the absence of any rotating parts allows usage for long-term monitoring under adverse environmental conditions. Their comparably high field modulation frequency and exclusion of sensing-electrode area modulation while in operation permit successful measurement of electric field strength in media where intense conductive and convective currents exist.

Interlaboratory comparison of radiated emission measurements using a spherical dipole radiator

An interlaboratory radiated emission comparison has been performed, comparing electric field strength measurements in the frequency range 30-1000 MHz at a 10 m open area test site. A spherical dipole radiator is employed as a reference emitter. Comparison results are presented in terms of measurement repeatability of electric field strengths measured at test sites for each frequency. Expanded uncertainty for the 95.45% confidence level is evaluated to be +5.6/-5.7 dB and +4.9/-4.8 dB for the frequency ranges corresponding to biconical and log-periodic antennas, respectively. Uncertainty analysis demonstrates that the uncertainty mainly stems from the antenna factor calibration, mismatch, the performance of a receiver and site imperfection.

A discussion of potential exposure metrics for use in epidemiological studies on human exposure to radiowaves from mobile phone base stations.

There is currently a high level of concern in many countries that exposure to radiowaves from mobile phone base stations may be hazardous to health. When investigating such suggested risks, epidemiologists need to define an exposure metric that can reliably discriminate between exposed and unexposed groups of people. We conducted a feasibility study to investigate if either short-term measurements of electric field strength, calculations of electric field strength, or distance from nearby mobile phone base stations could be used to develop a metric reflecting an individual's exposure to radiowaves. With electric field strengths in the range of 0.012-0.343 V/m, radiowaves from mobile phone base stations were found to give a material contribution to total exposure; however, stronger signals were frequently measured from other sources such as broadcast radio and television transmitters. Theoretical considerations and the measurements made during this work demonstrated that studies at the population level on suggested adverse effects of radiowaves from mobile phone base stations are not feasible since no valid metric for estimating historical exposures is currently available. The pace of radio infrastructure development is also such that today's measurements are unlikely to be good proxies for either past or future exposures. The complex propagation characteristics affecting the beams from base station antennas include shielding effects and multiple reflections from house walls and other buildings. These factors, combined with the presence of other environmental sources of radiowaves, cause distance from a base station to be a poor proxy for exposure to radiowaves indoors. It may be possible to adapt computer models developed by network providers to predict network coverage for epidemiological purposes; however, this has yet to be investigated. Furthermore, there is little evidence that presently justifies epidemiological studies being restricted to adverse effects of radiowaves from mobile phone base stations while neglecting radiowaves at other frequencies produced by different transmitters.

Highly Photoluminescent and Blue-Green Electroluminescent Polymers: New Silyl- and Alkoxy-Substituted Poly(p-phenylenevinylene) Related Copolymers Containing Carbazole or Fluorene Groups

A series of silyl- and alkoxy-substituted poly(p-phenylenevinylene) related copolymers containing carbazole and fluorene groups, poly[9,9-n-dihexyl-2,7-fluorenediylvinylene-alt-2,5-bis(trimethylsilyl)-p-phenylenevinylene] (PFBTS−PPV), poly[N-ethylhexyl-3,6-carbazolevinylene-alt-2,5-bis(trimethylsilyl)-p-phenylenevinylene] (PCBTS−PPV), poly[9,9-n-dihexyl-2,7-fluorenediyl-vinylene-alt-2-methoxy-5-(2-ethylhexyloxy)-p-phenylenevinylene] (PFMEH−PPV), and poly[N-ethylhexyl-3,6-carbazolevinylene-alt-2-methoxy-5-(2-ethylhexyloxy)-p-phenylenevinylene] (PCMEH−PPV), have been synthesized through the well-known Wittig polycondensation reaction. The synthesized polymers were completely soluble in common organic solvents and exhibited good thermal stability up to 400 °C. They showed UV−vis absorbance and photoluminescence (PL) in the ranges of 355−430 and 480−540 nm, respectively. The maximum emission peaks of dialkoxy-substituted PCMEH−PPV and PFMEH−PPV appeared at 520 and 540 nm, respectively, which were both blue-shifted about 55−75 nm compared to that of MEH−PPV. Especially, PCBTS−PPV and PFBTS−PPV showed much more blue-shifted emission maximum peaks at 480 and 495 nm corresponding to the blue and greenish-blue lights, respectively. Although PCBTS−PPV and PFBTS−PPV consist of conjugated segments without any kinked linkages, they showed far more blue-shifted emissions compared with other PPV related copolymers due to little electron-donating effect of the silyl substituent. Moreover, PFBTS−PPV and PCBTS−PPV showed extremely high PL efficiencies. Surprisingly, the PLeff (Φ = 0.81) of PFBTS−PPV is one of the highest values among the currently reported solid film PLeff of PPV derivatives. The single-layer light-emitting diode was fabricated in the configuration of ITO (indium−tin oxide)/polymer/Al. Electroluminescence (EL) maxima of PCBTS−PPV and PFBTS−PPV were shown at 480 and 500 nm, respectively, each corresponding to the blue and greenish-blue emission. The measurement of current vs electric field strength showed the threshold biases of PCBTS−PPV and PFBTS−PPV to be about 1.8 × 108 and 1.2 × 108 V/m, and PCBTS−PPV and PFBTS−PPV showed 13 and 32 times higher relative EL quantum efficiencies compared to that of MEH−PPV.

International comparison GT/RF 86-1 electric field strengths: 27 MHz to 10 GHz

This paper describes the international comparison of electric field strength measurements at frequencies between 27 MHz and 10 GHz (GT/RF 86-1). The participating laboratories were NIST, Pilot Laboratory, USA, National Physical Laboratory, U.K., NMi Van Swinden Laboratorium, the Netherlands, Institute Elettrotecnico National, Italy, Laboratoire Central des Industries Electriques, France, Electrotechnical Laboratory, Japan, Korea Research Institute of Standards and Science, Korea, and Technical University of Wroclaw, Poland.

Documenting Radiated Electromagnetic Field Strength in the Hospital Environment

Electromagnetic interference (EMI) in the hospital environment can cause medical devices to malfunction and poses a significant risk to patient safety. The purpose of this work was to document radiated electromagnetic (EM) field strength levels found in different areas of the hospital. Field strength measurements were made in various patient areas such as telemetry, intensive care, labor and delivery, emergency rooms, and operating rooms. Electric and magnetic field strength levels were highly dependent on environmental conditions within the hospital. Local sources present in a specific area (i.e., medical and communications equipment) were primarily responsible for field strength intensity in a given location. However, it was also determined that the hospital proximity to external transmitting antennas could affect ambient field strength in certain areas. In some cases, these field strength measurements exceeded the radiated EM immunity levels specified in the International Electrotechnical Commission (IEC) Standards for medical device electromagnetic compatibilitv (EMC).10–12Generally, medical devices must be able to withstand exposure to the field strength levels typical of the different environments in which they may be used. Therefore, the environment in which a medical device is used must be considered in the assessment and mitigation of EMI. This study was performed to document these environmental conditions and field strength levels in the hospital. The findings of this work show that 63% of all electric field strength measurements and 7% of all magnetic tield strength measurements collected in the hospital exceeded the proposed IEC immunity requirements for medical devices. Index under: electromagnetic environment, electromagnetic interference, EMI, radio-frequency interference, RFI, electromagnetic compatibility, EMC, medical device immunity, medical device emissions

An electric field measurement system, using a two-dimensional array of diodes

In hyperthermia induced by electromagnetic applicators, one way to obtain information about the energy absorption is by measurement of electric field strength (E). This paper describes a system which can measure E-distributions, using a two-dimensional array of diodes. It was designed to be used on patient skin, during hyperthermia treatments of superficial tumours, providing additional data for applicator power control. The first prototype consists of a sheet with Schottky diode sensors with a spacing of 2.5cm, connected to high-resistance leads, printed with carbon ink. The rectified diode voltages are passed through a multiplexer unit to an AD-DA card in a PC. The sensitivity of the sensors is linearly proportional to the electric field and to the length of the extended diode connection pins. Relative E-field distributions obtained with 64 sensors are updated within 1s. Phantom measurements, performed with the sensor matrix under a Lucite Cone Applicator (LCA) and under a 2 2 array of Current Sheet Applicators (CSAs) were compared with infrared measurements of the temperature rise after a short power pulse. A fair agreement was found between the square of the diode voltages and the infrared distributions. Movement of a single CSA over the sensor matrix can be visualized clearly by the system. The diode matrix E-field measurement system is sufficiently fast and accurate to give valuable feedback for power steering for an array of LCAs and CSAs. The system has the potential of being a helpful tool in other fields of quality assurance as well.

Detection of “Cold” Spectra from a Room-Temperature Ensemble: Magnetic Rotation Spectroscopy with Simple Interpretation in Terms of Molecular Pendular States

The anisotropic orientation of the figure axis of pendular molecules is directly detected by polarization spectroscopy for ICl in the excited A 3Π1 state. A simple geometric model is outlined that simulates all spectral features over a wide range of experimental parameters, without any fitting procedure. The experimental technique, closely related to magnetic rotation spectroscopy, strongly favors low rotational states and is also selective for ΔJ within a rotational band. Spectra obtained using a gas cell at room temperature thereby become even sparser and simpler than can be attained by cooling molecules to a few kelvin. Moreover, it provides a technique for local measurement of electric or magnetic field strengths without mechanical devices.

Methods and means of remote definition of clouds' electrical structure

A novel method for studying atmospheric electricity for aviation applications is developed. In the absence of thunderstorm activity, as in the case of nimbostratus, for example, both active and passive radar methods do not detect the zones of volume electric charges. However, it is known that the majority of cases of a lightning blow into plane occurs just in such clouds, when the electrical charge of the plane itself initiates the discharge. The electrolocation method based on the inverse problem of the electrostatics is used to detect volume electric charges. The airborne weather radar data are used to detect the location of cloud cells. This approach allows to obtain operative prognostic information about areas of electrical activity by applying electric field strength measurements en-route of flight. The key problems are: 1)development of reliable electric field sensors used for measurements under extreme severe conditions; 2)development of methods for data interpretation by using of the space-time characteristics of electric field. A short description of the developed electric field strength sensor, which is based on a novel method for measuring physical quantities is given. The essence of the method is described. Convergence of the proposed procedure of calibration is presented and confirmed by computer simulation. Research that has been carried out, allows to propose the scheme, construction and functioning algorithm of the adaptive electric field strength sensor. This sensor can operate in a condition of high severity. The parameters of non-linear working characteristics may vary uncontrollably due to continuous and unpredictable influence of different disturbing effects and destabilizing factors. Simulation of the measuring algorithm shows that under the condition of a casual change of steepness and displacement of the working characteristic within 50% of the rating value, an accuracy 1% in the measurement of electric field strength is being reached with not more than 10 calibration iterations.