Complex Metal Shielding Effectiveness Analysis Of Antenna Coupling Characteristics Of The Cavity

Electromagnetic pulse (EMP) is an electromagnetic phenomena with high electric field intensity and quite quite short rise time. It carries much engry that can cause serious EMI problem to the communication systems.Metal shielding structures are often used to protect electronic equipment from the radiation of electromagnetic pulse (EMP). However, some apertures have to be introduced on the cavity walls.In Chapter 2 of the thesis, shielding theory is reviewed at first, together with different waveforms of EMPs outlined and the definition of shielding effectiveness given.In Chapter 3, the shielding effectiveness of cylindrical cavities with different slots is investigated numerically with commercial software used. It is found that the shielding effectiveness is reduced significantly at the self-resonant frequencies of the cylindrical cavity. And evidently, the orientation and number of slots have strong effect on the inner field distribution.In Chapter 4, the shielding effectiveness of ladder-shaped metallic cavity is further investigated numerically, and in particular, the technique of window function is implemented in the shielding analysis.In Chapter 5, the coupling characteristies between double antenna elements are examined, which is useful for wireless communication. In particular, the effects of human head on the radiated field are studied, with some useful conclusions drawn finally.