Matthias Hampe

Single Summation Expression for the Impedance of Rectangular PCB Power-Bus Structures Loaded With Multiple Lumped Elements

In this paper, a single summation expression is derived for the impedance of rectangular printed circuit board (PCB) power-bus structures populated with numerous lumped elements. This is based on a summation formula of a Fourier series, which has already been used to derive a fast summation algorithm for calculating the impedance of bare multilayer PCBs. The theoretical results obtained with the single summation agree well with the results of the common circuit theory. The single summation expression allows for a very fast and accurate impedance computation of populated PCBs

Damping of cavity-mode resonances in PCB power-bus structures using discrete capacitors

In this paper, the impact of lumped elements connected to the power-bus of high-speed printed circuit boards is investigated and a computationally efficient expression of the resulting input impedance is derived. This result builds the theoretical basis of a novel technique suppressing cavity-mode resonances within the power-bus using discrete capacitors. Guidelines for an optimized selection and placement of these capacitors are specified. The theoretical results are well confirmed by measurements.

Improving the behavior of PCB power-bus structures by an appropriate segmentation

An effective and cost efficient method for suppressing cavity mode resonances within the power-bus of high-speed printed circuit boards is presented. It is shown that resonant modes can be completely suppressed by segmenting the power-bus into rectangular parts of smaller dimensions and connecting these parts suitably. For the case of identically shaped segments a double summation expression of the resulting voltage distribution within each part is derived. Furthermore, the impact of different connections between the segments is investigated. The theoretical results are well confirmed by measurements.

Improved impedance calculation of populated PCB power-bus structures

The impact of any number of lumped elements connected to the power-bus has been taken into account recently by using a modified modal summation. The formulas derived provide excellent results for calculating the power-bus impedance in the case of small admittances connected to the PCB. In the case of very large admittances, some errors in the calculations can be observed. In this paper, we further improve these formulas. The improved equations show a good agreement with the circuit theory even in the case of very large admittances connected to the PCB

Double and single summation expression for the impedance of populated PCB power-bus structures including asymmetrically connected components

In this paper the impact of lumped elements connected asymmetrically to rectangular PCB power-bus structures is investigated and a double summation expression for the resulting impedance is derived. Further, the double summation expression is reduced to a single summation expression by using a summation formula of a Fourier series. The analytical results show good agreement with measurements

Accurate measurement of transmission line parameters for automotive ethernet

In this work an accurate measurement setup is presented for determining the transmission line parameters of automotive cables. Both the complex line impedance and the complex propagation constant are measured in frequency domain for differential mode as well as common mode. Furthermore, the measured results are validated in time domain, both using measurements and simulations. Generally, a good agreement can be observed.

Damping of cavity-mode resonances in PCB power-bus structures using lossy slot resonators

In this paper, a novel technique suppressing cavity- mode resonances in PCB power-bus structures by using lossy slot resonators is presented. Guidelines for an optimized damping of the modal resonances are specified, which are based on rules derived recently for an appropriate selection and placement of damping capacitors. The effectiveness of the presented damping technique is shown by simulations as well as measurements considering several PCBs of different shape. I. INTRODUCTION Printed circuit boards (PCBs) for high-speed digital circuits use power and ground plane structures for power distribution. At higher frequencies this power-bus behaves as a cavity resonator (1)-(3). Resonances of the power-bus not only cause radiated emissions as EM interference, but also give rise to simultaneous switching noise as a signal integrity problem in high speed digital circuits. Therefore, a low impedance behavior of the power-bus is of great interest for engineers engaged in high-speed PCB design. Recently it has been shown, that discrete capacitors can be used successfully for damping of cavity-mode resonances in PCBs. Further, rules for an optimized selection and placement of these damping capacitors have been derived (4)-(6). In this work, we present a novel technique suppressing these modal resonances by using lossy slot resonators. Guide- lines for an optimized damping of the modal resonances are specified, which are based on the rules derived for damping capacitors. The effectiveness of this novel damping technique is exemplified by simulations as well as measurements con- sidering several PCBs of different shape.

Cross coupling between lightning conductor and signal lines within rotor blades

In this work we investigate the Electromagnetic Compatibility of an instrumented rotor blade. Particularly, the cross coupling between lightning conductor and signal lines within the rotor blade is calculated. Here, we use the well-known theory of multiconductor transmission lines. The calculations are compared with simulations. Generally, a very good agreement can be observed. Further, the efficienc of several EMC measures like twisting and shielding is analyzed. Finally, an appropriate separation distance is estimated to avoid voltage flash vers.

Generation of common-mode currents on PCB power-bus structures

In this paper, a significant generation process of common-mode currents on PCB power-bus structures is theoretically explained and experimentally investigated. Lumped elements connected asymmetrically to the power-bus are identified as the source of these common-mode currents. An analytical expression for the resulting common-mode current is derived, which agrees well with measurements. Furthermore it is shown, that the induced common-mode current can be reduced effectively by providing a low impedance behavior of the power-bus