Susceptibility Characterization of a Cavity with an Aperture by using Slowly Rotating EM Fields: FDTD Analysis and Measurements

This paper describes the evaluation of the susceptibility of a cavity with an aperture using the finite-difference time-domain (FDTD) method and experimentally. To reduce the computing time, the FDTD method is used for the radiation from the cavity and the susceptibility is obtained by using the reciprocity theorem. The cavity used here is modeled after a full-tower desktop enclosure with a 3.5-in bay. The susceptibility characteristics are evaluated by measuring outputs of a monopole antenna and transmission lines installed in the cavity. The susceptibility characteristics, using a three-dimensional (3-D) map, are studied from the computed and the measured results by applying slowly rotating electromagnetic fields to the cavity on a turntable. Measured and modeled results are in good agreement, indicating the merits of the proposed approach for susceptibility/immunity evaluation. Moreover, some discussions are made to check the susceptibility mechanism

Modeling Noise Coupling from Non-Parallel PCB Trace Routing

Coupling between PCB signal traces in proximity is of concern to PCB designers and EMC engineers. The behavior of noise coupling between non-parallel microstrip lines is studied in this paper by a full-wave numerical modeling method CEMPIE, designating a circuit extraction approach based on a mixed-potential integral equation formulation. Good agreement between the numerical results and measurements was obtained

Extracting CAD Models for Quantifying Noise Coupling Between Vias in PCB Layouts

A method to extract a lumped element prototype SPICE model is used to study noise coupling between non-parallel traces on a PCB. The parameters in this model are extracted using a PEEC-like approach, a Circuit Extraction approach based on a Mixed-Potential Integral Equation formulation (CEMPIE). Without large numbers of unknowns, the SPICE model saves computation time. Also, it is easy to incorporate into system SPICE net list to acquire the system simulation result considering the coupling between traces on the printed circuit board (PCB). A representative case is studied, and the comparison of measurements, CEMPIE simulation, and SPICE modeling are given

Noise Coupling from Single-Ended or Differential Signaling to Nearby Power Trace

Abstract Power and ground planes in the multilayer printed circuit board exhibits resonance in the frequency domain. Replacing the power supply planes by traces can considerably reduce the noise in the reference or ground, which leads to a dramatic reduction of the radiated electromagnetic fields. The power trace, however, may be coupled by nearby single-ended or differential signaling. The noise coupling from a single-ended or differential signaling to a nearby power trace is investigated in this work. First, the telegrapher's equations for multiconductor lines are applied. The analysis of the noise coupling is obtained by solving the telegrapher's equations using the mode decomposition technique. The results will be used as guidelines in the future interconnect design

A Modeling of Slot on the PCB Ground Plane by Using Genetic Algorithm

Abstract Modeling a slot at a ground plane is studied when a signal trace runs over it. Supposing the slot would work as a slot line with some terminal loads, we propose an experimental method to determine the parameters of the slot-line model by using a genetic algorithm (GA). At first, time-domain responses of the transmission line were measured by using a time-domain reflectometer (TDR). Then using GA, we determined a likely equivalent circuit and its parameters so as to agree with the measured and computed responses. As equivalent circuits of radiation impedance, parallel-CR, parallel-LR, series-CR, and series-LR circuits were assumed in advance. And we set possible ranges of their parameters and effective permittivity of the slot line too. Under such condition, GA determined the most likely model and parameters. By using the proposed method, it is expected to estimate a far-field emission pattern and to discover the mechanism of far-field emission and signal integrity. Introduction With the demand of high-density wiring on a printed circuit board (PCB), signal traces crossing slots in a ground plane are found. The slots are formed by a boundary of different voltage power planes. Such configuration models showing the interconnection of PCBs cause serious EMC problems. That is, they worsen a far-field emission and signal integrity. To overcome these problems, it is required to make clear the behavior of the slot on the ground plane. In this paper we consider PCB models shown i