Filip Vanhee

Automated Near-Field Scanning Algorithm for the EMC Analysis of Electronic Devices

This paper presents an automated procedure to determine the electric or magnetic near-field profile of electronic systems and devices in a given plane. It combines sequential sampling to determine the optimal coordinates of near-field scan points at arbitrary coordinates in the scanning plane. The effectiveness of the approach is illustrated by applying it to both a simulated and a measured printed circuit board example.

Efficient Reciprocity-Based Algorithm to Predict Worst Case Induced Disturbances on Multiconductor Transmission Lines due to Incoming Plane Waves

In this paper, an efficient reciprocity-based algorithm is proposed to predict the worst case voltages and currents induced by external plane waves at the ports of a multiconductor transmission-line system. The proposed algorithm consists of two main steps. In the first step, the far-field radiation of the multiconductor transmission-line system is fully characterized by a minimal number of full-wave simulations. In the second step, this information is used to efficiently evaluate the voltages and currents induced by a plane wave with arbitrary angles of incidence and polarization. After this, their worst case values can be easily found. The main advantage of the proposed algorithm is that no new full-wave simulations are required if different incoming plane waves or different sets of terminations at the ports of the multiconductor transmission-line system are to be considered.

In situ testing of large machines: Alternative methods for conducted emission measurements

On the legal aspect, the new European Directive on ElectroMagnetic Compatibility 2004/108/EC concerns also large machines. On a technical point of view, the special situation to characterise the EMC behaviour of large machines imply that current procedures are complex and very expensive, and in some cases even not possible. Adapted measuring methodologies and procedures are needed. As a response to this situation and within the European R&D Frameworks, the TEMCA2 project aimed to develop new and adapted methodologies for the assessment of EMC related to this type of industrial large machinery.

A new stripline measuring setup for the characterisation of conductive gaskets up to 18 GHz

Due to the impact of higher and higher frequencies, the Shielding Effectiveness (SE) characterisation of shielding gaskets at frequencies above 1 GHz is needed for on board shielding applications. Although the standard IEEE Std 1302™ - 2008 is covering the characterisation of shielding gaskets up to 18 GHz, the methods proposed in this standard are not applicable for these thin and small ‘on board’ gaskets. A method overcoming this problem is proposed in this paper.

Equivalent circuit model of the TEM cell electric and magnetic field coupling to microstrip lines

Electromagnetic compatibility (EMC) analysis of high-speed circuits is becoming mandatory due to the rapid increase in operating frequencies, RF interference and layout densities. Radiated susceptibility tests are important part of overall EMC analysis. In this paper the focus of investigation is on models of the coupling between a transverse electromagnetic (TEM) field generated by the TEM cell and the microstrip lines. In order to accurately model the coupling the models for microstrip lines, SMA connectors and TEM cell are developed. The coupling models are provided for transversal and longitudinal microstrip lines. The results for coupling capacitances are compared against results obtained by Method of Lines (MoL). The presented models are very accurate and include only passive elements, and therefore can be used for efficient coupling modelling between microstrip lines and the TEM cell septum.

Scalable Equivalent Circuit Modelling of the EM Field Coupling to Microstrips in the TEM Cell

A scalable circuit model of the electric and magnetic field coupling to microstrips placed on the top wall of a TEM cell is presented. The coupling parameters have been derived using approximating equations to reduce simulation times as much as possible. Simulation results of the resulting circuit model are validated by S-parameter measurements.

Towards a stripline setup to characterise the effects of corrosion and ageing on the shielding effectiveness of EMI gaskets

This paper introduces a novel measurement set-up dedicated to the characterization of the evolution of the high-frequency shielding-effectiveness of gaskets due to corrosion and ageing. The measurement set-up is based on the recently introduced stripline set-up which has been validated previously up to 40 GHz. Compared to the original stripline set-up, the adapted set-up has a removable “clamping module” which can be easily mounted and removed from the set-up. The clamping module allows to age the gasket inside e.g. a climate chamber while always keeping the gasket under the same compression rate. As the clamping module can be made out of different materials, it allows to study the influence of shielding-effectiveness of gaskets when applied to different materials. In order to avoid parallel leakage inside the measurement set-up, a high-performant gasket needs to be compressed below the module. Based on full-wave simulations, it is shown that the shielding-effectiveness given by this gasket underneath the clamping module is the main determining factor for the dynamic range of the set-up. In addition, a first set of measurements show the validity of the measurement set-up and approach.

Differences between NSA 94-106 and IEEE 299 LF magnetic shielding measurements

For the characterisation of the LF magnetic shielding of conductive materials two setups are available. Although for both methods, loop antennas are used, two different configurations are defined. The one referenced in NSA 94-106 (formerly NSA 65-6) is called the parallel setup. The one referenced in IEEE 299 (formerly MIL STD 285) is called the coplanar setup. When performing measurements under similar conditions, different values for the resulting shielding effectiveness (SE) are obtained. This paper will discuss the background why differences are occurring.

Shielding Effectiveness of anisotropic materials: How to measure?

In a number of applications, due to concerns such as weight and flexibility, shielding materials are used with anisotropic materials. Typically, in the case of some conductive textile materials, conductive yarns are only used in one direction (warp). Other materials will have different conductivity as a function of the direction, such as deployed metal grids. In this paper, measured Shielding Effectiveness SE results obtained by using different measuring setups are compared and discussed.

Influence of sample shape and size on the shielding effectiveness of EMI when characterized with the stripline test method

This paper studies the influence of a gaskets shape and size on its high-frequency shielding-effectiveness as measured with the stripline test method. Based on full-wave simulations it is shown that the main influencing parameter for the shielding-effectiveness is the gaskets conductivity. Through a comparison with the reverberation room method, it is shown that differences due to shape and size of the gasket are not related to the stripline set-up, but are a reflection of the true shielding effectiveness of the gasket.