Comparison of design and experimental frequency response of shielding efficiency of on-board cables for flying vehicles

Аuthors

Zhegov N. A.^1*, Kirillov V. Y.^2**, Klykov A. V.^3***, Tomilin M. M.^3***

1. Moscow Experimental Design Bureau “Mars”, 1-st Shemilovsky lane 16, building 2, Moscow, 127473, Russia
2. ,
3. Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

*e-mail: nzhegov@yandex.ru
**e-mail: kaf309@mai.ru
***e-mail: emc@mai.ru

Abstract

Purpose

The flying vehicle on-board cable network is subjected to electromagnetic interference due to its length. Electromagnetic interference immunity and susceptibility of on-board systems strongly depends on the on-board cables shielding efficiency. It is one of the main characteristic of flying vehicle on-board cables. When conducted current induced by electromagnetic interference flows over the external surface of shielding cover, the shielding efficiency is evaluated on the basis of well-known frequency response of coupling impedance. Coupling impedance of shielded cable can be calculated based on theoretical models or found experimentally with co-axial test setup. Coupling impedance models of shielded cable differ due to various approaches of describing the physical phenomenon of the in-phase voltage inducing in inner conductors of the cable, when current flows through external surface of shielding cover. Frequency responses of coupling impedance models differ from each other, which leads to the deference of frequency responses of external shielding efficiency, calculated on their basis.

The goal of this work consists in studying of coupling impedance models of on-board cables for flying vehicles, their divergence at the specified frequency range and comparison with experimental characteristics obtained using co-axial test setup.

Design/methodology/approach

The theoretical part is based on classical electrodynamics and electrical engineering. Elements of the complex variable theory and operational calculus were used as well.

Findings

The paper presents the results of theoretical and experimental coupling impedance and shielding efficiency frequency response of on-board cables for flying vehicles plotted in MATLAB. It also studies the differences between theoretical and experimental coupling impedance and shielding efficiency frequency response at specified frequency range. It is marked that shielding efficiency frequency response is valid for case of conducted current flows through the cable shielding cover in the absence of external electromagnetic field. In computing shielding efficiency the current through shielding cover must be of conductive origin rather than induced by the field of an external noise, i. e. it can be, for example, a reverse receiver-to-source current in case of non-symmetric connection. If a current through external shielding cover is induced by electromagnetic field effecting the on-board cable, the calculation of shielding efficiency based on coupling impedance frequency response can lead to significant erreos.

Current, which flows on cables shielding cover, should be conducted electromagnetic disturbance when shielding efficiency is calculated. For example, this current could be common-mode return current from the receiver to the source. Shielding efficiency calculation based on coupling impedance frequency characteristic can lead to significant errors in case the conducted current induced by electromagnetic field.

Completeness of the reseaerch

The presented paper is a part of the research on calculation of electromagnetic interferences induced in on-board cables of flying vehicles.

Keywords:

on-board cable, coupling impedance, electromagnetic interference, shielding efficiency

References

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