Jürgen Hillebrand

CAD model reconstruction of solder balls for the computationally efficient electromagnetic field simulation

In this paper three different methods for reconstructing CAD models of solder balls based on 3D computed tomography (CT) data are discussed. The resulting CAD model contains accurate geometrical data of the device which can be used for an electromagnetic field simulation using the finite difference time domain (FDTD) method. This allows a non-instrusive evaluation of the electrical parameters of passive circuits, in this case for solder balls or bumps. All three reconstruction methods presented here will result in simulation meshes with a significantly reduced number of mesh cells compared to a simulation directly based on the original CT data. This leads to a significant reduction of both memory usage and simulation time which is important for complex packages.

S-parameter extraction of passive sub-circuits using computed tomography scans and measured substrate material parameters

This paper presents a method for S-parameter extraction of passive sub-circuits embedded in complex microwave circuits. We employed computed tomography (CT) scans and measured substrate material parameters. The principle is based on the automatic reconstruction of CAD models from CT image data. Such CAD models represent the geometry of the actual manufactured passive microwave circuits and are suited for 3D electromagnetic field simulation to extract the S-parameters of these devices non-destructively. It is shown that by supplementing the simulation model with measured material parameters the agreement between the simulated S-parameters and the measured S-parameters can be improved. The proposed method has been applied to a passive 90° hybrid coupler, which is embedded in a hybrid power amplifier circuit.

Acceleration of a finite-difference method with general purpose GPUs - Lesson learned

Modern massively parallel graphics cards (GPGPUs) offer a promise of dramatically reducing computation times of numerically-intensive data-parallel algorithms. As cards that are easily integrated into desktop PCs, they can bring computational power previously reserved for computer clusters to the office space. High performance rates make GPGPUs a very attractive target platform for scientific simulations. In this paper we present the lessons learned during the parallelization of a finite-difference time-domain method, an inherently data-parallel algorithm frequently used for numerical computations, on the state of the art graphics hardware.

Simulation models for signal integrity analyses extracted from computed tomography scans — A case study for high-speed interconnects

In this paper, a method for signal integrity (SI) analysis based on computed tomography (CT) scans is proposed. SI analysis based on state-of-the-art measurements can be difficult to perform if the structures of interest are on inner layers of multi-layer boards, are enclosed by IC packages or if appropriate contacts for measurements cannot be provided due to cost and space reasons. In contrast to that, the proposed method is based on accurate simulation models which are extracted from computed tomography scans that can be used in electromagnetic (EM) field simulators for computer aided SI analyses. Such CT based models include fabrication tolerances so that computed EM field simulation results have a good correlation with common measurements. Compared to state-of-the-art SI measurements, the use of EM field simulators significantly simplifies SI analyses since a suitable simulation setup can be chosen without the requirement of test fixtures or limitations for contacting the structures of interest. The methodology is demonstrated on high-speed interconnects which are especially well-suited for the method.

Accelerating light scattering simulations of nanostructures by reconfigurable computing

In order to characterize nanostructures and nanosurfaces in production processes, measuring methods based on light scattering gain increasing importance. Thus the simulation capability of laser light scattering on surfaces with a size of several hundred or thousand wavelenghts in diameter and light scattering models on the nanometer scale are required to validate these new measurement techniques. This leads to a huge amount of computational complexity exceeding the resources of conventional desktop computers. In order to overcome this computational bottleneck two different approaches for massively parallel computing, namely graphic processing unit (GPU) computing and reconfigurable computing are compared in this paper. Both approaches are discussed with respect to the discrete dipole approximation (DDA) approach. Finally, a computer architecture incorporating both in a standard desktop system is presented.

Signal Integrity Model Extraction Based on Computed Tomography Scans—Analysis of the Required Voxel Resolution

Signal integrity (SI) analysis based on state-of-the-art measurements can be difficult to perform especially when the structures of interest are on inner layers of multilayer boards or are enclosed by IC packages. To enable an SI analysis in such cases the authors have recently developed a method that is based on the extraction of accurate simulation models from computed tomography (CT) scans. These models can be used in electromagnetic (EM) field simulators for computer-aided SI analyses. Such CT-based models include geometry variations or defects due to the manufacturing process so that computed EM field simulation results have a good correlation with common measurements. In order to identify the potential of the method an analysis of the required voxel resolution for the extraction of single-ended and differential striplines is presented. The analysis is based on the measurement uncertainty of length measurements in CT scans and an analysis of the propagation of uncertainty for the characteristic impedances of single-ended and differential striplines. This analysis shows that the voxel resolution of industrial CT scans is well suited for the extraction of accurate simulation models which can be used for an SI analysis.

Eine sicherheitsgerichtete Echtzeitprogrammiersprache für die Sicherheitsstufe SIL 3 gemäß DIN EN 61508

Vorgestellt wird eine sicherheitsgerichtete Echtzeitprogrammiersprache, die den Sicherheitsanforderungen gemas DIN EN 61508 fur die Sicherheitsstufe SIL 3 genugt. Die Programmiersprache basiert auf der Programmiersprache PEARL 90 nach DIN 66253 und ermoglicht die Erstellung von besonders verlasslich verifizierbarer Software fur sicherheitsgerichtete Echtzeitanwendungen. Die Programmiersprache bietet eine Programmierweise mit Funktionsplanen, Ursache-Wirkungstabellen, Meilensteindiagrammen und Kontrolltabellen, so dass Programme fur die Sicherheitsstufe SIL 3 mit einer vereinfachten Form der diversitaren Ruckwartsanalyse verlasslich verifizierbar sind. Die syntaktischen Regeln der Programmiersprache wurden zudem so definiert, dass sie inharent bekannte Quellen fur Programmfehler ausschliesen und die Sicherheit steigern.