scholarly journals Can Radiators Be Really Isotropic?

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
H. Matzner ◽  
E. Levine
Keyword(s):  
Current Density ◽  
Integral Method ◽  
Function Analysis ◽  
Finite Size ◽  
Surface Current ◽  
Real Space ◽  
Far Field ◽  
Surface Current Density ◽  
Power Radiation ◽  
Field Integral

In search for isotropic radiators with reasonable quality Factor (Q), bandwidth, and efficiency, one looks for practical radiators with a typical resonant length of . We present here a Green's function analysis in Fourier of a microstrip element and a far-field integral method in configuration (real) space of single and dual U-shaped elements. Both solutions analytically prove that the power radiation patterns are isotropic in nature (while the thickness and the width tend to zero), although the polarizations are not symmetrical in all cuts. It is also shown that the power isotropic U-shaped radiator, for which the surface current density is infinite, can be replaced by another finite-size radiator, having finite-surface current density, such that its far-field is exactly the same as the far-field of the U-shaped isotropic radiator.

scholarly journals Radar Cross-Section Formulation of a Shell-Shaped Projectile Using Modified PO Analysis

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
Mohammad Asif Zaman ◽  
Md. Abdul Matin
Keyword(s):  
Differential Geometry ◽  
Cross Section ◽  
Current Density ◽  
Surface Current ◽  
Radar Cross Section ◽  
Analysis Procedure ◽  
Physical Optics ◽  
Surface Current Density ◽  
Filtering Method ◽  
Good Agreement

A physical optics based method is presented for calculation of monostatic Radar Cross-Section (RCS) of a shell-shaped projectile. The projectile is modeled using differential geometry. The paper presents a detailed analysis procedure for RCS formulation using physical optics (PO) method. The shortcomings of the PO method in predicting accurate surface current density near the shadow boundaries are highlighted. A Fourier transform-based filtering method is proposed to remove the discontinuities in the approximated surface current density. The modified current density is used to formulate the scattered field and RCS. Numerical results are presented comparing the proposed method with conventional PO method. The results are also compared with published results of similar objects and found to be in good agreement.

Study on the Influence of Electrode Collocation to Electric Field Characteristic of ESP

2014 ◽  
Vol 875-877 ◽  
pp. 1683-1686
Author(s):  
Cheng Liang Jia ◽  
You Shan Sun ◽  
Chao Huang ◽  
Wan Peng Zhang ◽  
Fang Chen
Keyword(s):  
Electric Field ◽  
Current Density ◽  
Surface Current ◽  
Electrode Configuration ◽  
Electrode Gap ◽  
Average Current Density ◽  
Surface Current Density ◽  
Discharge Electrode ◽  
Field Characteristic ◽  
Average Current

A laboratory-scale ESP with new electrode configuration was established to investigate the electric field characteristic. Eight teeth prick line and prick plate with the length of 20mm were employed as discharge electrodes, respectively. The effects of discharge electrode type and electrode gap on V-I characteristic and surface current density were studied. The results showed that the optimum electrode gaps were 350-400mm for eight teeth line and 300-350mm for prick plate, which could obtained higher average current density and lower variance.

scholarly journals A Novel Tunable Triple-Band Left-Handed Metamaterial

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Si Li ◽  
Atef Z. Elsherbeni ◽  
Wenhua Yu ◽  
Wenxing Li ◽  
Yunlong Mao
Keyword(s):  
Current Density ◽  
Surface Current ◽  
Wide Band ◽  
The Other ◽  
Negative Permittivity ◽  
Negative Permeability ◽  
Surface Current Density ◽  
Density Distributions ◽  
Left Handed ◽  
Triple Band

A novel tunable triple-band left-handed metamaterial (LHM) composed of a single-loop resonator (SLR) and a variable capacitor-loaded short wire pair (CL-SWP) printed on both sides of a substrate is presented in this paper. The CL-SWP-based metamaterial (MTM) is a novel single-sided LHM. It is theoretically analyzed capable of extracting tunable negative permeability and a wide-band negative permittivity. We ran simulations for the CL-SWP-based MTM, the SLR-based MTM, and the proposed LHM. Together with the measured results, it is identified that this novel LHM exhibits a tunable triple-band left-handed (LH) property. With the increase of the loaded capacitance, one LH band is relatively stable, while the other two are moving towards lower frequencies with their bandwidth getting wider and narrower, respectively. The surface current density distributions indicate that the first LH band is mainly decided by the SLR, one of the rest 2 LH bands is mainly decided by the CL-SWP, and the other one is decided by the SLR and CL-SWP together.

scholarly journals Electrodynamic Parameters of a Coaxial Cable at Bipolar Pulses Propagation

2020 ◽  
pp. 25-37
Author(s):  
Yanis I. Bulbik ◽  
Fedor G. Zograf
Keyword(s):  
Boundary Conditions ◽  
Density Distribution ◽  
Current Density ◽  
High Speed ◽  
Surface Current ◽  
Current Density Distribution ◽  
Coaxial Cable ◽  
Surface Current Density ◽  
Speed Increase ◽  
Outer Conductor

All-in-interworking technology, based on IEEE 802.3 standard, was mainly developed for the separable media cabling and data transmission speed increase. Although the high-speed networking is already provided by a fiber optic cable, coaxial guides are in demand for similar applications. Time-domain analysis is undertaken to estimate electrodynamic states of inner and outer guiding conductors at periodic bipolar pulses propagation on a coaxial cable. An electric current density distribution on the cross-section of the inner conductor is obtained from a solution of Maxwell equations under periodic boundary conditions that are prescribed by a product of two functions. The first one is introduced implicitly for a profile of surface current density in the axial direction, while the other determines this profile transient states. As for shielding braid, which is the cable outer conductor, its current density distribution is derived from an analysis of field harmonics that penetrate into conductive subsurface layers under similar boundary conditions. It is also shown that prescribed implicative boundary conditions for both conductors allow to obtain, at least under auxiliary assumption, some completed formulae useful to the estimation of the pulses duration admissible decrease at their transmission on the coaxial cable. The paper contains some comparative and numerical results as well

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