scholarly journals Effective skin depth of EM fields due to large circular loop and electric dipole sources

2003 ◽  
Vol 55 (6) ◽  
pp. 301-313 ◽  
Author(s):  
Nagendra Pratap Singh ◽  
Toru Mogi
Keyword(s):  
Electric Dipole ◽  
Skin Depth ◽  
Circular Loop ◽  
Dipole Sources

A novel uniplanar wideband magneto-electric dipole antenna element

2017 ◽  
Vol 9 (10) ◽  
pp. 1983-1989
Author(s):  
Chen-Yang Shuai ◽  
Guang-Ming Wang ◽  
Ya-Wei Wang
Keyword(s):  
Electric Dipole ◽  
Wireless Local Area Network ◽  
Local Area Network ◽  
Ground Plane ◽  
Local Area ◽  
Dipole Antenna ◽  
Impedance Bandwidth ◽  
Antenna Element ◽  
Area Network ◽  
Circular Loop

A novel uniplanar wideband magneto-electric dipole antenna element is proposed in this paper. The proposed antenna is composed of the conventional bow-tie radiation patch as an electric dipole, a semi-circular loop, which works as a magnetic dipole, a coplanar ground plane, two directors with different lengths for enhancing gain, and a microstrip-to-coplanar stripline transition balun. The designed antenna adopts a small-size coplanar ground plane to achieve a uniplanar structure. Consequently, this method reduces the space size immensely and makes the antenna suitable for the array application. In addition, a tapered slot structure is utilized to improve impedance matching. The prototype of the proposed antenna was fabricated and measured. The measured results keep in good accordance with the simulated ones. The simulated results show that the proposed antenna obtains a broad impedance bandwidth of 60.5% from 2.25 to 4.20 GHz (voltage standing wave ratio [VSWR] ≤ 2) which can be applied for wireless local area network (WLAN) (2.4–2.484 GHz), worldwide interoperability for microwave access (WiMAX) (2.5–2.69/3.4–3.69 GHz), and long term evolution (LTE) (2.5–2.69 GHz). Meanwhile, the stable gain, low cross-polarization, stable unidirectional radiation patterns, and low back lobe are obtained within the operating frequency band. The array composed of the proposed antenna elements is also investigated in this paper.

On the electromagnetic response of a resistive cylinder buried in a conductive host

Geophysics ◽  
2014 ◽  
Vol 79 (6) ◽  
pp. E341-E351 ◽  
Author(s):  
Andrei Swidinsky
Keyword(s):  
Electric Dipole ◽  
Mineral Exploration ◽  
Skin Depth ◽  
Hydrocarbon Exploration ◽  
Electromagnetic Response ◽  
Dipole Source ◽  
Additional Information ◽  
Dipole System ◽  
Single Dipole ◽  
Current Systems

The frequency-domain electromagnetic response of a confined conductor buried in a resistive host has received much attention, particularly in the context of mineral exploration. In contrast, the problem of the electromagnetic response of a confined resistor buried in a conductive host has been less thoroughly studied. However, resistive targets are important in geotechnical and hydrologic studies, archaeological prospecting, and, more recently, offshore hydrocarbon exploration. I analytically address the problem of the electromagnetic response of a completely resistive cylindrical cavity buried in a conductive host in the presence of a simplified 2D electric dipole source. In contrast to the confined conductor, which channels and induces current systems, the confined resistor deflects current and produces additional eddy current systems in the conductive host. I apply this theory to model the response of a grounded electric dipole-dipole system operating over a range of frequencies from 0 Hz to 10 kHz, in the presence of a horizontal 5-m radius insulating cylinder located 1-m beneath the surface of a uniform earth. This represents a common hazard encountered during mining and civil engineering operations. Results show that such an insulating cavity increases the recorded electric field amplitude and phase delay at all transmitted frequencies. These observations suggest that a broadband electromagnetic prospecting system may provide additional information about the location and extent of a void, over and above a standard dipole-dipole resistivity survey. When the host skin depth is much larger than all other length scales, the response can be approximated by an equivalent single dipole unless the cylinder’s radius is much larger than its distance from the transmitter. This result provids a useful rule of thumb to determine the acceptable range over which a resistive target can be modeled by a distribution of dipoles.

scholarly journals A More Efficient Observation Way With Electric Dipole Sources

2020 ◽  
Author(s):  
xianxiang wang ◽  
yongbang Chang ◽  
Juzhi Deng
Keyword(s):  
Comparative Analysis ◽  
High Precision ◽  
Numerical Algorithm ◽  
Electric Dipole ◽  
Apparent Resistivity ◽  
Monotonic Functions ◽  
Electromagnetic Data ◽  
Static Effect ◽  
Anomalous Bodies ◽  
Dipole Sources

Abstract The Ex and Hz amplitude are monotonic functions of the resistivity, and numerical algorithm can be utilized to obtain the high-precision apparent resistivity for all frequencies. On this basis, we focus on the comparative analysis of the resolution for Ex field, Hz field, and Cagniard apparent resistivity to conductive and resistance targets, which proves that the Ex field may have a better resolution for the resistance bodies, and the Hz field can better identify the conductive target. Besides, the electromagnetic data is often distorted by the static effect, which seriously affects the application effect of the electromagnetic method. The influence of the static effect on the Ex field, Hz field, is also analyzed. The apparent resistivity based on the Ex field and Cagniard apparent resistivity are severely affected by the static effect which can cover deep anomalous bodies, but the apparent resistivity based on the Hz field is almost unaffected by the static effect. At last, a more efficient observation way is provided for the resistance and conductive targets, respectively.

THE QUASI-STATIC FIELD OF AN ELECTRIC DIPOLE EMBEDDED IN A TWO-LAYER CONDUCTING HALF-SPACE

1967 ◽  
Vol 45 (6) ◽  
pp. 1981-2002 ◽  
Author(s):  
J. T. Weaver
Keyword(s):  
Electromagnetic Field ◽  
Half Space ◽  
Electric Dipole ◽  
Plane Surface ◽  
Static Field ◽  
Skin Depth ◽  
Numerical Calculations ◽  
Dimensionless Form ◽  
Special Cases

Solutions are derived for the quasi-static electromagnetic field produced by an electric dipole located in the upper layer of a two-layer conducting half-space. Two orientations of the dipole are considered, (i) normal to, and (ii) parallel to the plane surface of the conductor. The well-known solutions for the corresponding fields of a dipole in a uniform conducting half-space emerge as special cases. Numerical calculations of the amplitudes and phases of the field components are made for a dipole situated midway down an upper layer one "skin depth" thick. The results are presented in a dimensionless form and are dependent only on the ratio of the conductivities of the two layers.

scholarly journals Study on the localization of the electric dipole sources

2007 ◽  
Vol 56 (9) ◽  
pp. 5180
Author(s):  
Wu Chong-Qing ◽  
Zhao Shuang
Keyword(s):  
Electric Dipole ◽  
Dipole Sources

Hydromagnetic radiation from electric and magnetic dipoles in the magnetosphere

1969 ◽  
Vol 47 (16) ◽  
pp. 1643-1656 ◽  
Author(s):  
A. K. Sundaram
Keyword(s):  
Magnetic Field ◽  
Magnetic Dipole ◽  
Electric Dipole ◽  
Static Field ◽  
Radiation Characteristics ◽  
Magnetostatic Field ◽  
Magnetic Dipoles ◽  
The Waves ◽  
Dipole Sources ◽  
The Magnetic Field

This paper deals with the radiation characteristics of elementary electric and magnetic dipoles in a homogeneous, anisotropic, cold plasma of infinite extent with a uniform magnetostatic field. The cases treated include the electromagnetic sources taken parallel and perpendicular to the magnetostatic field. In all cases expressions for the field components are obtained which are valid at frequencies well below the ion cyclotron frequency. It is found that electric and magnetic dipole sources when oriented perpendicular to the magnetic field excite both ordinary and extraordinary modes. For the ordinary mode, the waves are guided in both directions within cones of small apex angle aligned with the static field. When the dipole sources are aligned with the magnetic field, it is found that the electric dipole excites only the ordinary mode leading to guided wave propagation, while the magnetic dipole excites only the extraordinary mode. In all cases the waves propagate at Alfvén speed. The radiation characteristics are isotropic for the extraordinary mode excited by the perpendicular electric dipole and are nearly isotropic for the aligned magnetic dipole. For other cases the radiated power is concentrated in opposite directions along the static field.

Transient marine electromagnetics in shallow water: A sensitivity and resolution study of the vertical electric field at short ranges

Geophysics ◽  
2014 ◽  
Vol 79 (1) ◽  
pp. E39-E49 ◽  
Author(s):  
Pavel O. Barsukov ◽  
Edward B. Fainberg
Keyword(s):  
Shallow Water ◽  
Electric Dipole ◽  
Near Field ◽  
Marine Electromagnetics ◽  
Transverse Resistance ◽  
Vertical Electric Dipole ◽  
Vertical Electric Field ◽  
Horizontal Electric Dipole ◽  
The Time Domain ◽  
Dipole Sources

We analyzed the sensitivity of transient step-off responses of shallow-water marine controlled-source electromagnetic configurations, specifically, horizontal electric dipole sources and vertical electric dipole receivers in the near field of the time domain ([Formula: see text]). The capabilities of this configuration were compared with commonly used configurations, specifically, horizontal electric dipole sources and horizontal electric dipole receivers in the frequency domain ([Formula: see text]). By examining some simplified models of local hydrocarbon reservoirs representing separate resistive bodies of limited size buried at different depths in the conductive sediments, and an example of a complex 3D geologic structure, the applications of [Formula: see text] and [Formula: see text] configurations and their limitations in terms of depth, size, and transverse resistance were evaluated.

The Modeling of TEM Responses Simulated by Multi-Transmitter

2012 ◽  
Vol 450-451 ◽  
pp. 1518-1521
Author(s):  
Xin Gong Tang ◽  
Wen Bao Hu ◽  
Liang Jun Yan
Keyword(s):  
Electric Dipole ◽  
Field Survey ◽  
Dipole Source ◽  
Good Resolution ◽  
Controlled Source ◽  
Anomalous Body ◽  
Transient Electromagnetic ◽  
Electromagnetic Responses ◽  
Anomalous Bodies ◽  
Dipole Sources

Using one or two electric dipole transmitters in the Controlled source electromgnetic method, this paper calculate the transient electromagnetic responses of one and two 3D conductive anomalous bodies in the layered earth by varying the number and intensity of the dipole sources. The results of the models show that satisfactory resolution can be achieved when only one dipole source is used. The stronger the intensity of the electric dipole source, the better resolution for the anomalous body for the same offset. When two electric dipole transmitters laid each side of one 3D body, it means that the anomalous body locates in the middle of the sources and the resolution to the target becomes poor. The numerical results of the transient electromagnetic responses of two 3D bodies also support the idea that resolution is not good when two transmitters are used in each side of the targets simultaneously. As the conclusion, in order to get good resolution to the target, multi transmitters laid different side of the geological target should not be used the same time in the field survey.

Sign in / Sign up

Export Citation Format

Share Document