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We suggest a few kinds of extended classical oscillators in this study. We present a few specific modules for examining these oscillators' behavior. This will be an essential component of a broader web-based scientific computing platform that is in the works. The modeling and synthesis of radiating antenna designs is also taken into consideration as a potential use case for Melnikov functions. Additionally, we discuss strategies for achieving probabilistic control over system perturbations. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new modified planar Kelvin–Stuart model. We demonstrate some modules for investigating the dynamics of the proposed model. This will be included as an integral part of a planned, much more general Web-based application for scientific computing. Investigations in light of Melnikov's approach are considered. Some simulations and applications are also presented. The proposed new modifications of planar Kelvin–Stuart models contain many free parameters (the coefficients g i , i = 1 , 2 , ... , N ), which makes them attractive for use in engineering applications such as the antenna feeder technique (a possible generating and simulating of antenna factors) and the theory of approximations (a possible good approximation of a given electrical stage). The probabilistic control of the perturbations is discussed. [ABSTRACT FROM AUTHOR]

In low frequency band, miniaturized EMC(Electromagnetic Compatibility) test antennas are mostly electrically small antennas, which have the problems of high antenna factor and low test sensitivity. To solve the problem, based on active matching technology, the electrically small antennas loaded with negative impedance converter circuit and field effect transistor high-impedance input circuit are simulated and analyzed respectively. The simulation results show that the field effect transistor high-impedance input circuit has advantages over the negative impedance converter circuit in the ability of reducing antenna factor and the stability of circuit, and is helpful to the design and implementation of miniaturized EMC test antenna. The test results of the miniaturized EMC test antenna loaded with field effect transistor high-impedance input matching circuit show that, in 2~30 MHz, antenna factor can be improved by 22~46 dB compared with the EMC test antenna without matching circuit. [ABSTRACT FROM AUTHOR]

This paper demonstrates the design, modeling, and analysis of a small size 180 × 165 × 1.6 mm3 printed broadband Vivaldi antenna for electromagnetic compatibility measurements. The proposed antenna is intended to be utilized as a reference antenna for emission and immunity tests inside the EMC Chamber through the band (0.8–5.5 GHz). Exponentially tapered slots were created based on mathematical equations to form an end-fire radiation antenna. Furthermore, microstrip and slot line stubs were employed to tune the impedance bandwidth. This antenna could be considered a 2-D Horn antenna with a size reduction of 64% and 67% since both antennas, Vivaldi and Horn are based on the same principle. Two rectangular slots were engraved near the feeding point to reshape and enhance the gain at lower frequency bands. Furthermore, the realized gain has been improved by approximately 3.5 dB and reached up to 10.7 dBi by introducing a pair of triangular reversal slots at the top edges of the structure. Moreover, this antenna has specifications that make it a suitable candidate to work as a reference antenna inside the EMC chamber compared to the classical Horn antenna offered for sale (PowerLOG® PRO 30800 and TBMA4). [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive design approach for a biconical log-periodic dipole array (Bi-log) hybrid antenna optimized specifically for electromagnetic interference (EMI) measurements. The antenna's elements, scaling function, feed structure, balanced-to-unbalanced (Balun) geometry, and key parameter selection are carefully considered to achieve enhanced broadband testing capabilities. The proposed compact Bi-log hybrid antenna is optimized using Taguchi's method within the frequency range of 30 MHz to 6 GHz. The optimization focuses on the discontinuity of the antenna factor (AF), incorporating miniaturized elements. The dimensions of the proposed antenna are minimized, with a length of 95 cm, width of 148.5 cm, height of 60 cm, and weight of 2.5 kg. Simulation results and experimental validations demonstrate its efficacy through comparison. Optimization results indicate that the voltage standing wave ratio VSWR < 2 (with 5 dB attenuator) and symmetry < ±0.5 dB also meet the regulatory standards according to ANSI C 63.4. This makes the proposed antenna suitable for use in various types of semi-anechoic chambers. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive design approach for a biconical log-periodic dipole array (Bi-log) hybrid antenna optimized specifically for electromagnetic interference (EMI) measurements. The antenna’s elements, scaling function, feed structure, balanced-to-unbalanced (Balun) geometry, and key parameter selection are carefully considered to achieve enhanced broadband testing capabilities. The proposed compact Bi-log hybrid antenna is optimized using Taguchi’s method within the frequency range of 30 MHz to 6 GHz. The optimization focuses on the discontinuity of the antenna factor (AF), incorporating miniaturized elements. The dimensions of the proposed antenna are minimized, with a length of 95 cm, width of 148.5 cm, height of 60 cm, and weight of 2.5 kg. Simulation results and experimental validations demonstrate its efficacy through comparison. Optimization results indicate that the voltage standing wave ratio VSWR < 2 (with 5 dB attenuator) and symmetry < ±0.5 dB also meet the regulatory standards according to ANSI C 63.4. This makes the proposed antenna suitable for use in various types of semi-anechoic chambers.

This article presents the design, modeling, and fabrication of a printed log-periodic biconical dipole array antenna (PLPBDA) for electromagnetic compatibility (EMC) measurements. The proposed structure used bow tie-shaped dipoles instead of typical dipoles to achieve a size reduction of 50% and bandwidth enhancement of 170% with the help of PCB technology. Furthermore, the balanced feeding method and the modifications in bow tie-shaped dipole dimensions were utilized to obtain broad bandwidth of 5.5 GHz (from 0.5 GHz to 6 GHz). This structure comprises 12 dipole elements with a compact size of 170 × 160 × 1.6 mm, reflecting low fluctuations gain of about (4.6–7) dBi with the help of an extra dipole. Moreover, the achieved frequency and radiation characteristics (simulated and measured) agree with each other and are compatible with the results of classical EMC antennas. The achievements of this structure showed promising results compared to both literature reviews and reference antenna Hyper LOG® 7060 offered for sale. [ABSTRACT FROM AUTHOR]

This paper presents the antenna factor (AF) of sleeve dipole antennas (SDA) with coaxial-cable balun for electromagnetic compatibility (EMC) applications. The AF characteristics are considered by varying parameters such as the length of the central dipole and the size and spacing of the sleeve elements. The coupled integral equations for the unknown current distributions on each element are derived and solved by applying Galerkin's method of moments. A SDA with a 180 cm central dipole has similar characteristics as a conventional biconical antenna but with a physical volume 86% lower than that of the Schwarzbeck BBA9106 biconical antenna. Calculated antenna factors of the SDA are compared with measured results. A sleeve dipole antenna for electromagnetic interference (EMI) measurements with an appropriate antenna factor could be realized.

In this paper, we propose a compact-standard antenna method (C-SAM) for antenna calibration above 1 GHz. The test-site evaluation of the fully-anechoic room (FAR) condition satisfied the free-space conditions. When the C-SAM was compared with conventional antenna calibration methods, the maximum deviation was within ±0.18 dB for the 1–18 GHz frequency range. Unlike the conventional antenna calibration methods, the proposed method is a simple standard antenna method that calculates the antenna factor of the antenna under calibration (AUC) with only one site insertion loss (SIL) measurement of an antenna calibration site that meets free-space conditions. Therefore, the C-SAM is the best candidate for antenna calibration owing to the method’s simplicity and cost-reduction potential.

Accurate modeling of partial discharge (PD) within gas-insulated switchgear (GIS) has become of paramount significance to improve the utilization of ultrahigh frequency (UHF) sensors within such capital assets. Providing better insight on how electromagnetic (EM) waves propagate within GIS systems provides valuable information that can be used to determine the optimal allocation of UHF sensors. Thus far, most existing models are not considering the full complexity of the GIS systems due to the many associated challenges and the high computational demand of such system modeling. In this work, a GIS system is modeled using the Maxwell solver of COMSOL multiphysics. CIGRE sensitivity verification recommendations (CSVR) are used to inject UHF signals using an internal sensor. Then, two external sensors, placed on the outer belt of dielectric spacers, are used to capture the radiated EM waves. The electric field distribution at selected frequencies is presented and discussed under two operating conditions for disconnecting switches. The modeled GIS contains many barriers, including two bends, multiple sudden changes in the outer to inner diameters ratios, six dielectric spacers, and two disconnecting switches. Time-domain simulation results are also presented to provide an insight into the attenuation properties of EM waves due to the different barriers. Finally, a comparison between simulated and measured results has been carried out to verify the modeling accuracy. The results show that GIS systems form complex structures for the EM waves, and fully understanding the wave propagation can be tedious. [ABSTRACT FROM AUTHOR]

This paper considers circular antenna arrays comprised of symmetrical dipole radiators applied in communication, navigation and monitoring systems. Despite their widespread use, a number of significant issues is underinvestigated. Among them are frequency dependence of the antenna factor (the ratio of the electric field intensity module to the voltage amplitude at the load connected to the output terminals) of the circular antenna array elements in the correct electrodynamic setting. The purpose of this paper is to analyse the antenna factor frequency dependence of a single dipole antenna with different geometry and load both in free space and as circular antenna element. The estimation of phase difference error between the circular antenna array elements caused by their cross coupling is also of interest.Specific expressions are obtained for the antenna factor of the dipole antenna for single-mode and three-mode approximations. The limits of their applicability in frequency band are considered. The solution to the coupled integral equations is obtained using the Galerkin method with piecewise sinusoidal current distribution and with an arbitrary number of basis functions for eight- and four-element circular antenna array. This solution may be generalized to an arbitrary number of circular antenna array elements. It is demonstrated that to improve the antenna factor frequency dependence it is advisable to use dipole antennas with high-resistance load, as well as with large diameter. Phase errors for different circular antenna array element signals are considered with respect to the reference element. The dependence of these phase errors on the circular antenna array geometry is presented. It is concluded that there are significant oscillations of the antenna factor when the dipole is the part of the circular antenna array. They are caused by cross coupling between the circular antenna array elements, which significantly depend on the element spacing. The results presented may be of interest to phase direction finder development engineers.

This article investigates the design, modeling, and fabrication of small-size (150 × 90 × 1.6 mm) broadband printed biconical antenna. The proposed antenna is intended for use a reference antenna for electromagnetic interference measurement inside the EMC chamber. The reflection coefficient (S11-parameter) is verified by modeling the equivalent circuit of the structure in terms of lumped elements. This structure offers a −10 dB impedance bandwidth (from 0.65 GHz to 2.3 GHz) with the tapered balun feeding method. Therefore, it has a high probability of estimating the electromagnetic waves emitted from several applications such as GSM, LTE, UMTS, 3G, Wi-fi, Bluetooth, ZigBee and more. The simulated standard antenna parameters are compatible with the measured parameters results. Furthermore, azimuth omnidirectional radiation pattern and well-realized gain (3.8 dBi) are achieved, reflecting good values of antenna factor compared to the commercial design.

In this paper, scanning tunneling microscope (STM) light emission (STM-LE) from alkanethiol self-assembled monolayer (SAM)-covered Au film has been probed in the Kretschmann configuration. The films were deposited on the smooth plane of a hemispherical glass prism. STM-LEs from the tip–sample gap into the vacuum (tip-side emission) and into the prism (prism-side emission) were investigated. Our experimental results showed that the tip-side emission was scarcely found, and the prism-side emissions were successfully detected due to the enhancement of Kretschmann configuration. It was also found from the experimental study that the peak intensity of STM-LE spectra become smaller, accompanying the redshift of the peak position with the rise in thickness of the alkanethiol SAM film. The main focus of this paper is to explore the behavior of electron tunneling into the SAM-covered Au film. In order to explain these phenomena, we have designed different models regarding the tip–sample gap structure. Among these models, the antenna factor successfully explains the cutoff energy shift of STM-LE spectra. According to this model, the cutoff energy shows redshift when the electronic transition occurs at the Au–S interface layer and the amount of the shift depends on the strength of the transitions. [ABSTRACT FROM AUTHOR]

This article is dedicated to the study of the images method, using half-wave dipoles on the dielectric ground plane, which is different from the widely known images method, which uses antennas on a ground plane (PEC). A review of the propagation models commonly used have been discussed. This paper presents a study of the images method at an air- dielectric ground plane interface. The experimental verification has been carried out by measuring the electric field as a function of distance, using half-wave dipole antennas for a frequency of 2.6 GHz, on a ceramic ground plane, for horizontal and vertical polarization. Ceramic floor at frequencies of f = 2.6 GHz can be considered a lossless dielectric media due to its negligible losses. The results of the images method have been modeled and discussed with a current image that has amplitude and phase for the dielectric ground plane. • The paper discusses and purposes the images method on the dielectric ground plane, different of the well known PEC ground plane. • The model of this paper compares with other models: Log-distance, ITU-R, Keenan-Motley, Okumura-Hata and Walfish-Ikegami. • The floor at microwave frequencies behavior is considered like lossless dielectric media. • This paper extend the method of images on the dielectric ground planes. • The experimental measurements have been achieved using a transmitting and a receiving antenna versus distance. [ABSTRACT FROM AUTHOR]

The continuous, non-intermitted service of electrical grids relies on the reliability of their assets, e.g., power transformers. Local insulation defects can result in serve failures such as breakdowns with severe subsequent costs. The prevention of such events is crucial. Hence, partial discharge (PD) activity at power transformers is evaluated directly in the factory before shipment. Additionally, PD activity can be monitored during service using the ultra-high frequency (UHF) method. In this contribution, a calibration procedure is proposed for the UHF method. The calibration process is required to ensure both, reproducibility and comparability of UHF measurements: Only a calibrated UHF measurement procedure can be introduced supplementary to IEC 60270 in acceptance tests of power transformers. The proposed calibration method considers two factors: The influence of the UHF-antenna’s sensitivity and the PD recorder characteristics including accessories such as cable damping, pre-amplifier, etc. The former is addressed by a characterization of UHF sensors using the standard antenna factor (AF) in a gigahertz transverse electromagnetic (GTEM) cell. The PD recorder’s influence is corrected by using a defined, invariable test signal as reference for all recording devices. A practical evaluation of the proposed calibration procedure is performed in a laboratory setup using different UHF recording devices and UHF sensors using artificial PD signals and real voltage-driven PD sources.

The slanted wire grounded monopole is a very simple system. It’s fed from a wire skirt, exhibits a resistive impedance and the inductive reactance can be nullified with a variable capacitor. Since the physical antenna behavior is not always clearly explained, to show the vertical radiation characteristics of the antenna height versus the antenna radius, as it is modified by the slanted wire, we present this paper. The high angle radiation is larger compared to the standard cylindrical series fed monopole of the same height, and for this reason in the U.S. the F.C.C. prohibited this system to be used at night. This paper determines the actual antenna characteristic according to the tower height and effective radius using the moment method software code. If one sets the antenna height to be used with similar radiation pattern as the traditional cylindrical series fed monopole this radiating system presents a very low area to ice accumulations and allows placing lightning beacon and other R.F. radiating systems with no technical problems. [ABSTRACT FROM PUBLISHER]

Now-a-days researchers are very much concerned to evaluate Specific Absorption Rate (SAR) at different human organs due to the Electromagnetic (EM) wave radiation coming from cell phone antennas or other wireless communication devices at radiofrequency (RF). But, the time has come to change the vision slightly toward the effect of RF on agricultural field and plant kingdom. The purpose of this paper is to study the effects of RF radiation coming from Base Station Antennas (BSAs) on a Money plant. In this work, the radiation coming from a 2.4 GHz base station at the occupational and general public exposure levels prescribed by ICNIRP have been taken into consideration and then SAR induced inside a Money plant has been calculated. Shielding effectiveness (SE) provided by the Money plant has been experimentally measured and calculated in the frequency range of 2.35 GHz to 3.0 GHz. Maximum value of Local Point SAR at 2.4 GHz induced inside the Money plant for occupational and general public exposure levels are found to be 9.50 W/kg and 1.88 W/kg respectively. Whereas, Maximum value of SE obtained by the simulation and measurement are found to be 9.48 dB and 9.01 dB respectively. [ABSTRACT FROM AUTHOR]

This paper presents the antenna factor characteristics of a calculable dipole antenna with a hybrid balun, installed above ground plane vertically and horizontally, using Method of Moments (MoM). An expression for the antenna factor is formulated using the concept of power mismatch loss. The input impedance and effective length of the antenna, which are in the formula of the antenna factor, are calculated using the MoM. The results show that the antenna factors above a ground plane are agreed with the free space antenna factors within ± 0.14 dB. The horizontal antenna factors are varied more by 0.2 dB than the vertical antenna factors. [ABSTRACT FROM AUTHOR]

A new way is proposed, and verified by experiment, to measure the free-space antenna factor (Fa) of biconical antennas over 30 to 300 MHz by the standard antenna method. The antennas were horizontally polarized above a metal ground plane. The usual method of calibrating electromagnetic compatibility antennas is to place two antennas at a given separation in a horizontal plane. Biconical antennas have a uniform H-plane pattern, making it possible to stack the antennas in a vertical plane. The (Fa) measured with the new method is in close agreement (difference less than 0.6 dB) to that with the vertically polarized method from the FDIS IEC international standard CISPR 16-1-6. Because the antennas are stacked vertically, a smaller ground plane can be used. Because the antennas are horizontally polarized, the vertically routed cable is orthogonal to the antenna so the interaction of cable and antenna is minimized. [ABSTRACT FROM AUTHOR]

This study discusses the relevance of the methodology applied to process indoor noise measurements in the mediumwave band in order to provide reference noise levels. The knowledge of noise levels is necessary for planning radio services and for analyzing the influence of radio noise in the human body. This work presents a description of the parameters for characterizing the noise-measurement antennas, and explains how these parameters are determined. The terms for specifying the noise intensity and the methods for processing radio-noise measurements are described. The characteristics of an ideal and an actual antenna in the medium-wave band are presented, showing the relevance of the difference between the ideal and actual antennas when radio-noise levels are calculated. This work presents the differences in the noise levels given by different processing methods, using an actual antenna and a theoretical antenna. Finally, the results of several recently published noise measurements that have been processed by different methods are presented, and compared with the values predicted by ITU-R P.372. [ABSTRACT FROM AUTHOR]

Abstract: The standard site method was used to measure antenna factor. Based on calculation of antenna factor uncertainty, ways of more precise estimation of uncertainty, leading to uncertainty reduction, are presented. Using uncertainty standards together with known approaches to radiated emission measurement uncertainty calculation, a model of antenna factor measurement and an equation for calculation of its uncertainty were derived. Possible steps to reduce resultant measurement uncertainty are described, including an analysis of correlation, and acknowledgment of frequency dependence. The uncertainty was calculated in 25 frequency points in the range from 30MHz to 1000MHz. Furthermore, various calculations of uncertainty are executed to examine the suggested effects on the uncertainty value. [Copyright &y& Elsevier]