Study Of The Field Distribution In GTEM Cell And GTEM Cell Application In Shielding Effect Measurement

The principle result of the FDTD (Finite-Difference Time-Domain) method is set forth concisely in the thesis. Some key technical problems about using the method to calculate the field distribution in GTEM Cell (GHz transverse electromagnetic transmission cell) are discussed in detail and solved. For example, the gridding dissect; inspiring source's setting and calculating; boundary terms' setting (including boundary terms' on slat exterior, boundary terms of slope slant inner GTEM Cell and absorbing boundary terms); calculating parameter's setting and inspecting peak value etc are involved.The feature of the field distribution in GTEM Cell and its application in EMC is systematically studied here, such as: the numerical value calculation and measure in hollow GTEM Cell; the numerical value calculation in GTEM Cell when metal DUT added; and the analyse and comparison of both results. Through comparison, the calculation results are in accord with the measure results, the field in GTEM Cell's efficient workground is an equal field. In efficiency workground, when the change of electric field intension is less than 4dB, which can meet the need of EMC measure. When adding the metal case, electric field intension increased. This is because, the region which is not nil between the soleplate and core plate is minished; portrait heft (z heft) accretion. Those indicate that the mode of field changed, characteristic of transverse electromagnetic wave become worse.Shielding measure of computer case is also studied and improved in this thesis. The possible part to be shielded is systematically analyzed, and the shielding method is given relevantly. The case which can be used to do experiments are designed. The method of how to use GTEM Cell to measure the case's shielding effect is studied. The shielding effect with varies shielding material are measured. Quantities of measurement data and valuable conclusion are given. In the end, this thesis also stated the measurement of the shieldingeffect to common computers before and after adding shielding materials, and the antenna effect of cable that commonly exists in these experiments.