Davy Pissoort

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.

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.

Accurate Hotspot Localization by Sampling the Near-Field Pattern of Electronic Devices

This paper describes a new automated scanning algorithm to identify hotspots (regions with electric or magnetic near-field values above a specific threshold) in the planar near-field profile of electronic systems. The algorithm sequentially determines a set of optimal scanning coordinates where experimental measurements should be performed. The result of the process is a heat map that clearly outlines the presence and localization of hotspots. The efficacy of the proposed algorithm is validated on a measured and a simulated example.

Correlating the High-Frequency Shielding Performance of 'On-Board' Gaskets when Characterized using a Stripline or Reverberation Room Method

This paper compares the shielding performance or shielding effectiveness of gaskets for on-board applications when determined with either a stripline method or a reverberation room method. The shielding performance is considered in the frequency range from 1 up to 40 Ghz. Similar to PCB-level enclosures, gaskets for on-board applications differ significantly from other shielding products, therefore requiring an appropriate definition for their shielding effectiveness. It is shown by full-wave simulations that a 3rd order polynomial fit of the shielding effectiveness obtained with the stripline method correlates well with the shielding effectiveness obtained with a reverberation room method, in which case the shielding effectiveness is defined as the ratio between the radiated/received power with and without gasket.

Adaptive Stopping Criterion for Fast Time Domain Characterization of Microwave Components

This letter proposes a novel adaptive stopping criterion that facilitates a fast time domain characterization of microwave components. By successively computing a rational macromodel based on time-limited transient responses of the microwave component under study, the proposed stopping criterion limits the number of time steps required to capture the frequency behavior up to a predefined accuracy level. Therefore, it is particularly useful for systems where the transient responses decay slowly.

Auxiliary Dipoles to Compensate for the Finite Size of the Planar Scanning Area in Near-to-Far-Field Transformations

A novel algorithm to obtain an accurate representation of the far-field emissions starting from a finite planar scan of the magnetic near-field is proposed. The algorithm introduces so-called auxiliary sources that compensate for the finite size of the scan area. While previous works typically introduce equivalent sources to represent the fields inside the scanning area, the auxiliary sources introduced in this paper approximate the fields outside of the scanning area. The auxiliary sources are located within the printed circuit board under the scanning area at the locations where the scanned field strengths are above a prechosen threshold. Their complex values are chosen such that they accurately represent the fields at the edge of the scanning area. Several numerical examples show that the application of these auxiliary sources considerably improves the accuracy of the obtained far-field.

Influence of the interaction between antenna currents and return currents on the coupling between digital interfaces and on-board antennas

Due to the integration of wireless modules and on-board antennas at printed circuit board (PCB) level, design engineers are faced with even more difficult challenges to avoid intra-system electromagnetic interference issues. When starting to design a printed circuit board, the first rule is to partition the printed circuit board such that noisy components are placed physically far away from sensitive components. This rule relies on the phenomenon that at moderately high frequencies, return currents tend to stay in proximity of and close to their signal currents. Unfortunately, on-board antennas most often induce antenna currents which are distributed over a large part of the PCBs power/ground planes. As a result, significant interference might even happen with circuits which are placed physically far away from the antennas location. During the whole design process, the engineer has to make sure that the overlap area between the antenna currents and the return currents paths of the critical circuits is as minimal as possible. This is achieved by properly placing circuits, keeping track of the antenna current distribution, and by avoiding all return path discontinuities. “Intuitive” solutions as putting a slot around the critical circuits might actually lead to higher electromagnetic interference levels. Hence, full-wave simulations which allow for visualizing all current distributions and their interactions, are an important asset in aiding the design process. The simulation process becomes a key element in a judicial component placement to minimize the interaction between antenna currents and return currents in PCB designs.

Removing the Spectral Leakage in Time-Domain Based Near-Field Scanning Measurements

This paper describes the application of a new and easy to implement algorithm to EMI near-field scanning measurement results obtained with a time-domain-based measurement system. The algorithm aims to reduce the effect of spectral leakage on amplitude and phase of the measured field components. The proposed algorithm significantly increases the accuracy of the measured electromagnetic near field with a limited extra computational cost. The versatility and effectiveness of the proposed algorithm is shown on both simulated and measured data. It is shown that for situations with one single frequency component or with several well-separated frequency components, the algorithm is as performant as the application of a flat top window and outperforms other types of windows. However, as soon as the frequency components approach each other implying their spectral leakage patterns overlap, the proposed algorithm outperforms the application of a flat top window.

Two-Dimensional Magnetostatic Finite-Element Simulation for Devices With a Radial Symmetry

This paper proposes a 2-D magnetostatic finite-element solver for radially symmetric devices, complementary to the standard Cartesian and axisymmetric solvers, which are typically used for translatory and cylindrically symmetric configurations. In contrast to the Cartesian and axisymmetric cases, a specific difficulty is encountered due to the particular dependence of the magnetic vector potential on the radial coordinate caused by the requirement for radial symmetry. Dedicated finite-element shape functions are developed such that the partition-of-unity property, consistency, and convergence of the formulation are guaranteed. Implementation aspects and modeling peculiarities are discussed. The new solver is validated for models in which analytical solutions exist. The modeling accuracy of the new 2-D solver is compared with a 3-D model for the calculation of the electromotive force and the electromagnetic torque of a twin-rotor axial-flux permanent magnet synchronous machine.