solved. As in many complicated problems, attempts are made to simplify the analysis by considering small subproblems which can be treated independently. The total solution to the main problem is then looked upon as a combination of such solutions. In the area of electromagnetic pulse (EMP), one can divide the analysis of a particular system into the following subareas: Much effort has been expended in trying to understand EMP phenomenology and propagation. A similar statement can be made about the external interaction and circuit areas. Although some effort has also been spent in developing the sophistication of the analytical tools in the internal interaction area, it is generally agreed that the highest degree of uncertainty exists in this area [I] , [2] . The area of internal interaction begins at the skin of the system (aircraft, for example) and treats the radiation and propagation within the confines of the system. Thus, it is presumed that the exterior interaction problem, as well as the penetration problem through the aircraft skin, has already been solved. Quantities of interest to be determined in an internal interaction calculation are typically voltage and current levels at specified input ports to electronic components within the system. 1) study of the production of Em (EM PhenomenologY), Often the terms GC~~~~~~~~~~,, and GG~~~~~~~~ are used

Topological Concepts for Internal EMP Interaction

An efficient circuital model is developed to predict the shielding effectiveness of an enclosure with an aperture array excited by a plane wave. First of all, the impedance of the aperture array is expressed as a function of the spacing between apertures, the radius of apertures, the incident angle, and the thickness of the perforated plate. Then, a multiple modes equivalent circuit method is proposed to evaluate the shielding effectiveness of the enclosure at frequencies up to multiple resonances region. Finally, the efficiency and accuracy of the method are demonstrated by comparing its results with analytical results from other equivalent circuit methods and numerical results from the transmission-line modeling method. The method outperforms the traditional equivalent circuit methods in that it takes into account several crucial geometrical parameters, the properties of the incident plane wave, the mutual coupling between apertures, and multiple modes propagation effect at the same time, thus having better accuracy. Meanwhile, the method provides a reasonable accuracy with a low computational burden, as compared with more complex numerical methods.

An Improved Circuital Method for the Prediction of Shielding Effectiveness of an Enclosure With Apertures Excited by a Plane Wave

An efficient analytical model based on electromagnetic (EM) topology has been developed for predicting the EM field coupling with a lossless penetrated transmission line (TL) of which the termination loads are located in two enclosures, respectively, excited by an internal vertical monopole and an external plane wave of oblique incidence. Firstly, the electric fields generated by the plane wave are calculated based on Bethe's aperture coupling theory and scalar wave function method. Then, the topology network of the EM interaction is established according to the analysis of the interference paths and the coupling mechanism from sources to the TL. Finally, the electric current induced at the line terminations is obtained by combining the generalised Baum-Liu-Tesche equation and the Agrawal's model. The analytical model has been successfully verified by the finite difference time domain method over a broad frequency range, and costs less time and fewer computational resources than numerical methods, which provides guidance for the field-to-line coupling in complex multiple enclosures against different sources.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-smt.2017.0363

Efficient analytical method for the coupling to penetrated transmission line in multiple enclosures based on electromagnetic topology

An efficient analytical model for the transfer impedance and admittance of a noncoaxial/twinax braided–shielded cable with apertures on its sheath is proposed by generalizing the old Vance's and Kley's formulas, and it is derived using the complex analyses with an appropriate conformal mapping. Therefore, such a noncoaxial cable is converted into a coaxial one which can be studied using the traditional multiconductor transmission line method. It is shown that the aperture inductance is related to the position of the inner conductor and the radial position of each aperture on its sheath. In addition, the modal domain analysis is performed to obtain the common-mode (CM) and differential-mode (DM) transfer impedance/admittance of the twinax braided–shielded cable, with CM and DM currents inside the inner conductors examined. The proposed model is validated by comparing the results with that obtained by the method of moments (MoM)-based commercial software FEKO. It is found that the uniform distribution of the apertures on the sheath reduces the induced DM current significantly

Efficient Analytical Model for the Transfer Impedance and Admittance of Noncoaxial/Twinax Braided–Shielded Cables

The popularity of the electric vehicle (EV) brings us many challenges of electromagnetic compatibility (EMC). Automotive manufacturers are obliged to keep their products in compliance with EMC regulations. However, the EV is a complex system composed of various electromagnetic interferences (EMI), sensitive equipment and complicated coupling paths, which pose great challenges to the efficient troubleshooting of EMC problems. This paper presents an electromagnetic topology (EMT) based model and analysis method for vehicle-level EMI prediction, which decomposes an EV into multi-subsystems and transforms electromagnetic coupling paths into network parameters. This way, each part could be modelled separately with different technologies and vehicle-level EMI was able to be predicted by algebra calculations. The effectiveness of the proposed method was validated by comparing predicted vehicle-radiated emissions at low frequency with experimental results, and application to the troubleshooting of emission problems.

https://www.mdpi.com/2079-9292/8/3/364/pdf

A Topology-Based Approach to Improve Vehicle-Level Electromagnetic Radiation

Electromagnetic radiation from transmission lines is an important topic in electromagnetic compatibility. Thus, this paper aims at developing an analytical technique to evaluate radiated electric field and shielding effectiveness (SE) of shielded cable. The induced voltages and currents on the screen are modeled by the surface transfer impedance with Kley's method. Then, based on the Hertzian dipole technique, the radiating transmission line is decomposed into small-length hypothetical dipoles and the total electromagnetic radiation can be replaced by the summation of the dipoles. After that, the SE expression of shielded cable is obtained according to the electromagnetic calculation results, which is defined by using transfer impedance. Finally, numerical simulations are carried out by using a commercial software computer simulation technology (CST) to validate the proposed approach. The expressions give a way of allowing fast parametric analysis of radiation and SE during the design phase of the electrical and geometrical configuration of shielded cable.

An Analytical Method for Radiated Electromagnetic and Shielding Effectiveness of Braided Coaxial Cable

Conventional analytical and numerical approaches are inefficient for the analysis of electromagnetic (EM) coupling effect on a printed circuit board (PCB) in complicated electric systems. This paper develops a hybrid method based on the combination of electromagnetic topology and analytical method or full-wave simulation. A coupling mechanism of PCB in a nested shielding enclosure is established, and the EM interactions from exterior fields to interior PCB are determined by the way of conductive and radiation coupling interference. The total load disturbance voltage of PCB trace is obtained by solving the BLT equation of the two interference paths. In this paper, the full-wave simulation method is adopted to calculate the electric field and numerical integration method is applied to solve the BLT equation. The results of the proposed method are in good agreement with the result of a commercial full-wave tool, which confirms its validity. Compared to numerical simulation, the proposed method simplifies the modeling process significantly and possesses better efficiency.

A Hybrid Method for Calculating the Coupling to PCB Inside a Nested Shielding Enclosure Based on Electromagnetic Topology

Reduced technique for modeling electromagnetic immunity on braid shielding cable bundles

In this paper, an efficient analytical approach for calculating the load response of a transmission line(TL) with interference source in interconnected equipment was proposed based on Bethe's theory and BLT equation. Using the corresponding dyadic Green's function and Bethe's theory, the fields around the TL excited by a hertzian dipole is determined. Then, the load disturbance is obtained with the help of Agrawal's model and BLT equation. The results are in good agreement with CST simulation, which establishes the validity of the analytical method. Compared to numerical simulation, the proposed method possesses better efficiency and consumes less memory.

http://ieeexplore.ieee.org/iel7/7510516/7522714/07522857.pdf

Pei Xiao

Papers

An Analytical Method for Radiated Electromagnetic and Shielding Effectiveness of Braided Coaxial Cable

A Hybrid Method for Calculating the Coupling to PCB Inside a Nested Shielding Enclosure Based on Electromagnetic Topology

An Improved Circuital Method for the Prediction of Shielding Effectiveness of an Enclosure With Apertures Excited by a Plane Wave

Reduced technique for modeling electromagnetic immunity on braid shielding cable bundles

An analytical approach for calculating load response of a transmission line with interference source in interconnected equipment