Current Issue : July - September Volume : 2015 Issue Number : 3 Articles : 4 Articles
It is well-known that if an E-field integral equation or an H-field integral equation is applied alone in analysis of EM scattering from\na conducting body, the solution to the equation will be either nonunique or unstable at the vicinity of a certain interior frequency.\nAn effective math model is presented here, providing an easy way to deal with this situation. At the interior resonant frequencies,\nthe surface current density is divided into two parts: an induced surface current caused by the incident field and a resonance surface\ncurrent associated with the interior resonance mode. In this paper, the presented model, based on electric field integral equation\nand orthogonal modal theory, is used here to filter out resonant mode; therefore, unique and stable solution will be obtained.The\nproposed method possesses the merits of clarity in concept and simplicity in computation. A good agreement is achieved between\nthe calculated results and those obtained by other methods in both 2D and 3D EM scattering....
The objective of this paper is to design miniaturized narrow- and dual-band filters for WLAN application using zero order\nresonators by the method of least squares. The miniaturization of the narrow-band filter is up to 70% and that of the dual-band\nfilter is up to 64% compared to the available models in the literature. Two prototype models of the narrow-band and dual-band\nfilters are fabricated and measured, which verify the proposed structure for the filter and its design by the presented method, using\nan equivalent circuit model....
A novel configuration of quad-band bowtie antenna suitable for wireless application is proposed based on accurate equivalent\ncircuit model. The simple configuration and low profile nature of the proposed antenna lead to easy multifrequency operation.\nThe proposed antenna is designed to satisfy specific bandwidth specifications for current communication systems including the\nBluetooth (frequency range 2.4ââ?¬â??2.485GHz) and bands of the Unlicensed National Information Infrastructure (U-NII) low band\n(frequency range 5.15ââ?¬â??5.35GHz) and U-NII mid band (frequency range 5.47ââ?¬â??5.725GHz) and used for mobile WiMAX (frequency\nrange 3.3ââ?¬â??3.6GHz). To validate the proposed equivalent circuit model, the simulation results are compared with those obtained\nby the moments method of Momentum software, the finite integration technique of CST Microwave studio, and the finite element\nmethod of HFSS software. An excellent agreement is achieved for all the designed antennas. The analysis of the simulated results\nconfirms the successful design of quad-band bowtie antenna....
A new concept of metal spiral coaxial cable is introduced. The solution to Maxwell�s equations for the fundamental propagating\nTEM eigenmode, using a generalization of the Schwarz-Christoffel conformal mapping of the spiral transverse section, is provided\ntogether with the analysis of the impedances and the Poynting vector of the line. The new cable may find application as a medium\nfor telecommunication and networking or in the sector of the Microwave Photonics. A spiral plasmonic coaxial cable could be\nused to propagate subwavelength surface plasmon polaritons at optical frequencies. Furthermore, according to the present model,\nthe myelinated nerves can be considered natural examples of spiral coaxial cables. This study suggests that a malformation of the\nPeters angle, which determines the power of the neural signal in the TEM mode, causes higher/lower power to be transmitted in\nthe neural networks with respect to the natural level. The formulas of the myelin sheaths thickness, the diameter of the axon, and\nthe spiral g factor of the lipid bilayers, which are mathematically related to the impedances of the spiral coaxial line, can make it\neasier to analyze the neural line impedance mismatches and the signal disconnections typical of the neurodegenerative diseases....
Loading....