Circuital and Numerical Models for Calculation of Shielding Effectiveness of Enclosure with Apertures and Monitoring Dipole Antenna Inside (original) (raw)
Related papers
2014
In this paper, numerical model of metal enclosure with apertures and monitoring antenna is considered for the purpose of accurate shielding effectiveness calculation. TLM method incorporating wire node model is used to account for the presence of monitoring dipole or monopole antennas used in practice to detect the level of electromagnetic field at selected points inside the enclosure. Numerical model is first verified through comparison with experimental results and then used to study an impact of physical parameters of considered antennas on shielding properties of rectangular enclosure and shift of its resonance frequencies. In addition, both antennas are mutually compared in terms of their influence on detected level of electromagnetic field inside enclosure.
Shielding effectiveness of a rectangular enclosure with a rectangular aperture
Electronics Letters, 1996
In this paper, a numerical model of rectangular enclosure with apertures and a real receiving dipole antenna is considered for the purpose of accurate electric shielding effectiveness calculation. Dipole antenna is often used in practice to measure the level of electromagnetic field at some points inside the enclosure in order to estimate its shielding efficiency. Transmission-line matrix (TLM) method enhanced with compact wire model is applied here to generate the numerical model that takes into account the presence of receiving dipole antenna inside the enclosure. Using the proposed model, impact of receiving antenna on electric shielding effectiveness is illustrated on the example of enclosure with three different patterns of rectangular apertures and compared with the case when antenna presence is neglected. A plane wave propagating in a direction normal to the front wall of enclosure is assumed as an external interference signal.
Progress In Electromagnetics Research C, 2016
The main section of this paper comprehensively analyzes electrical shielding effectiveness (ESE) of enclosures with rectangular apertures for producing valuable information used in electromagnetic interference and compatibility guiding enclosure designers of electronic devices. Firstly, results of conventional analytical equivalent circuit model, measurement and simulation with computer simulating technology (CST TM) of ESE for an enclosure with a single aperture size are compared to improve closeness in different models at 0-1 GHz. After getting a suitable simulation model, all possible parameters with detailed cases are examined to approach beneficial conclusions. Especially, size of enclosure, aperture size, aperture shape, configuration and number of apertures, probe position parameters that affect ESE are investigated. Also, some double parameters are analyzed together to achieve detailed review as two enclosure dimensions, two aperture dimensions and probe position with enclosure depth. Therefore, three-dimensional graphical investigations are performed. Obtained results of these parametric approaches are explained with acceptable reasons. Finally, detailed and itemized comments are given about simulated results of ESE parameters, which are collected from previous sections.
Serbian Journal of Electrical Engineering, 2020
Generally, most of the electronic equipments need a metallic enclosure in order to mechanically protect and electrically shield the interior printed circuit boards (PCBs) and subsystems. But in practical situations, the apertures or slots of various forms are essential parts of the shielding enclosure for thermal dissipation, CD-ROMs, connectors, I/O cabling and so on. The performance of shielding enclosures for high-speed digital systems is compromised by these inevitable discontinuities on enclosure. To minimize the electromagnetic interferences and susceptibility risks by these discontinuities, the shielding enclosures with apertures should be designed based on thorough analysis about the electromagnetic coupling mechanism through apertures. In this paper, the effect of apertures and oblique incident plane wave on shielding effectiveness of the enclosure is studied with the Circuital Approach, and the Finite-Difference Time-Domain (FDTD) method, the simulated SE data are verified...
Analytical formulation for the shielding effectiveness of enclosures with apertures
IEEE Transactions on Electromagnetic Compatibility, 1998
An analytical formulation has been developed for the shielding effectiveness of a rectangular enclosure with an aperture. Both the magnetic and electric shielding may be calculated as a function of frequency, enclosure dimensions, aperture dimensions and position within the enclosure. Theoretical values of shielding effectiveness are in good agreement with measurements. The theory has been extended to account for circular apertures, multiple apertures, and the effect of the enclosure contents.
IET Science, Measurement & Technology, 2009
In this paper, a numerical model of rectangular enclosure with apertures and a real receiving dipole antenna is considered for the purpose of accurate electric shielding effectiveness calculation. Dipole antenna is often used in practice to measure the level of electromagnetic field at some points inside the enclosure in order to estimate its shielding efficiency. Transmission-line matrix (TLM) method enhanced with compact wire model is applied here to generate the numerical model that takes into account the presence of receiving dipole antenna inside the enclosure. Using the proposed model, impact of receiving antenna on electric shielding effectiveness is illustrated on the example of enclosure with three different patterns of rectangular apertures and compared with the case when antenna presence is neglected. A plane wave propagating in a direction normal to the front wall of enclosure is assumed as an external interference signal.
Simulation of metallic enclosures with apertures on Electrical Shielding Effectiveness
Electromagnetic shielding of metallic enclosures with an aperture is simulated by means of COMSOL in this paper. The effect of the polarization type, the thickness of material and material type on electrical shielding effectiveness has been investigated to give suggestions to enclosure designers to get better performance against to EMI. It is obtained that locating rectangular aperture in vertical position with respect to the direction of source results in better electrical shielding performance. Performance of an enclosure whose thickness is about a skin depth is 6dB worse than the enclosure whose thickness is in the order of five times skin depth. As expected, higher conducting materials need to be preferred rather than poor one. Silver, aluminum, cupper and chrome are in the order of better to worst.
Electric and magnetic shielding effectiveness of metallic enclosures with apertures
2006 Asia-Pacific Microwave Conference, 2006
This paper presents a detailed study of the shielding effectiveness of a rectangular metallic enclosure with apertures by using an analytical formulation and experimental study. The theories developed by other researchers have been extended to take into account the contribution of multimode of propagation in the enclosure. Both the electric and magnetic shielding effectiveness were calculated as a function of frequency, enclosure dimensions, aperture dimensions, various aperture positions and observation points by employing a transmission line equivalent circuit approach. Simple modifications were included to account for multiple apertures. Generally, the analytical results of the shielding effectiveness are in good agreement with measurement results which were conducted in a GTEM cell.
The electrical and magnetic shielding effectiveness of a metallic shield perforated with numerous apertures is evaluated in this work using the Transmission Line Method (TLM). Here an appropriate admittance that takes the mutual coupling between the apertures into account is considered as to represent the array of apertures. The fundamental formulas are included to deal with the case of a rectangular enclosure with numerous small rectangular apertures in this model. The electric and magnetic shielding effectiveness are compared in this paper. The observation points are taken along one of the rectangular enclosure dimension i.e., depth of the enclosure and then observed the each point for the shielding effectiveness of both electric and magnetic fields. Shielding effectiveness is calculated for the oblique incidence of single and multiple apertures. Simulation results demonstrate that: lower frequencies display better shielding than higher frequencies; the effectiveness of shielding of a single hole is worse than of a multi-hole for identical areas. The electric shielding effectiveness increases continuously with the angle of incidence and the magnetic shielding effectiveness decreases continuously with the angle of incidence.
Numerical Investigation of Monitoring Antenna Influence on Shielding Effectiveness Characterization
2014
─ This paper deals with an impact of receiving antenna placed in a metal enclosure on an electromagnetic field distribution within the enclosure, and thus on its shielding effectiveness. In an experimental setup, a frequently used tool for measuring the electromagnetic field level at certain points within the enclosure is a dipole antenna connected to a measuring instrument via a coaxial cable. For modeling a coupling between the electromagnetic field and antenna in the protective enclosure we use the Transmission-Line Matrix (TLM) method, enhanced with the compact wire model. The numerical model is verified through comparison with the available experimental results and then used to investigate the influence of physical dimensions of dipole antenna and its cable connection on the detected level of shielding effectiveness. Index Terms ─ Dipole antenna, enclosure, shielding effectiveness, TLM wire model.