Research On Energy Selective Structure Design And Navigation Protection Application

In recent years,electronic information equipments are increasingly susceptible and delicate to intense electromagnetic interference(EMI)and electromagnetic(EM)attacks as its integration level develops.In addition to natural strong EM threats,factitious intense EMI and EM weapons are gradually maturer.Electronic information equipments for military and civil usages are all facing severe threats.Hence,it is important to study adaptive EM protection methods with theory and project signality.In this paper,the main focus is on the “front door” adaptive protection technology of sensitive equipment.The author designs miniaturized bandpass structure and ultra wideband structure of energy selective surface(ESS),and studies the application in navigation protection.The specific work is as follows:1.ESS based on miniaturized bandpass structure is designed.First,the properties of nonlinear device are tested and circuit model parameters is extracted.Then qualitative analysis of frequency bandwidth characteristics and adaptive protection principle is given by the equivalent circuit of miniaturized structure with nonlinear device loaded on.Next,the structure is improved depending on analysis of electric field distribution and practical needs.Thus,induced voltage of the position where the nonlinear devices loaded is more concentrated,and the improved structure can protect equipment from circular polarized wave adaptively.Miniaturized bandpass structure designed in this work has simple mechanism and well angle stability due to its small unit cell.2.ESS based on ultra wideband structure is designed.Through the research that multilayers' coupling in conjunction with the characteristics of each layer are combined to realize the frequency response,the S-band ultra wideband protective structure is improved from conventional linear structure of ESS.The qualitative analysis of ultra wideband characteristic is expounded by equivalent circuit simulation and filter theory.The rationality of location of nonliner devices loaded is confirmed by the analysis of induced electric field distribution.Ultra wideband structure designed in this work has simple mechanism and good ultra wideband protective performance with low insertion loss and high shielding effectiveness.3.Beidou navigation and positioning receiving antenna protection radome is designed.Cross energy selective structure is selected according to the circular polarized characteristic of navigation antenna.On the premise of not affecting the proper functioning of antenna,the navigation antenna protection radome is designed by integrating ESS and original radome without changing the shape of antenna and original radome.The antenna performance and positional accuracy are not significantly affected by the protection radome,as supported by testing several parameter indices.Then the high field experiment is designed.This research on navigation protection application of ESS is an exploration of ESS from verification samples to application product.