Fdtd 시뮬레이션
Often, data from military EMI/EMC laboratories with a plain shielded room test environment are considered to have a much higher measurement uncertainty. The poor measurement accuracy (or repeatability) is due to measurement equipment, antenna factors, site-measurement reflection errors, and cable movement optimization. The differences between measurements taken at different test laboratories, or even within the same test laboratory on different days, can easily be as high as ☖ dB.
While most engineers take great comfort in data from measurements, the repeatability of radiated emissions measurements in a commercial EMI/EMC test laboratory is unreliable. Typically, modeling tools have ‘perfect’ isotropic antennas, which may measure fields approaching from direct directions much differently than the real-world antenna would.Īnother aspect of model validation by measurement is the accuracy of the measurement itself. This antenna will have an antenna factor that varies with frequency and will have significant directionality as well. Another important consideration is the physical antenna used for the measurement. If radiated emissions are to be used for validation, then the ground-reference in the test site, the movement of the antenna from one to four meters above the ground-reference plane (for commercial EMC testing), must be included. If direct probing methods are used to measure/model printed circuit board effects, then the loading imposed by the test equipment (typically 50 ohms) must be included in the simulation, or the results are not likely to agree. Care must be taken to include measurement limitations in the model. It is vital that the exact same measurement configuration is used in the simulation. Extreme care must be used if simulations are to be validated using measurements. However, measurements are not always accurate. In fact, when performed carefully, measurements are an ideal way to validate simulations. Measurements are the most common way to validate a simulation. This paper is a summary of the various model validation techniques.
FDTD 시뮬레이션 FULL
This article will discuss some of the various techniques that can be used to validate full wave simulations.Ī number of papers on computational modeling validation have been presented at a wide variety of conferences in the past few years. Some level of validation should be performed on every group of models to make sure that the geometry is correctly represented, that the source in the model is realistic, and that the results are in accord with the underlying laws of physics. This assumption is extremely dangerous and should be avoided. There is a sense by some that if a modeling tool has been validated in the past (with measurements or some other technique), then the user can trust all the results from this tool in the future. Some extra work must be done to verify that the results are correct for the intended simulation. Unfortunately, there is no guarantee that the model was created properly, that the essential physics of the problem have been included, or that the results have been interpreted properly.
FDTD 시뮬레이션 SOFTWARE
Given a particular model, software tools will provide an accurate result based on that input or model.
Full-wave and quasi-static simulation tools using many different modeling techniques are in common use for a wide variety of EMI/EMC problems. difference 482 m Resolution 10 m Site m, 28.5 dbm, 948 MHz Transmitter Site m, 24.9 dbm, 948 MHz Prediction height 1.The need to validate simulations and model results has never been more vital. difference 394 m Resolution 50.0 m 91.0 m, 43.8 dbm, Transmitter MHz Prediction height 1.5 m 3D view of the database (z-axis scaled with factor 5) Scenario I : Area around Grab/Murrhardt, Germany Scenario II : Hong Kong, China Predictions for transmitter location 1 Scenario Information Number of buildings 3306 Topo. 실내 교외 도시 Scenario I : Institute for Radio Frequency Technology, University of Stuttgart, Germany Scenario I : Area around Grab/Murrhardt, Germany Scenario II : Hong Kong, China Typical modern office building! Material Scenario Information concrete and glass Total number of objects 353 Number of walls 170 Resolution Transmitter Prediction height 0.50 m 0.90 m, 20 dbm, 1800 MHz 0.90 m 3D view of the modern office building Scenario I : Institute of Radio Frequency Technology, University of Stuttgart, Germany Scenario Information Topo.