Research On Testing Method Of Shielding Effectiveness For Electromagnetic Shielding Clothing

The users of electromagnetic shielding clothes gradually turn to mass consumergroup from special consumer group with the increasing deterioration environment ofelectromagnetic radiation and the people’s growing protection awareness of it, whichmakes the development and application of electromagnetic shielding clothes present tobe different development trend. However, if the electromagnetic shielding clothes canreach to the shielding effectiveness, have the function of security and protection and howto measure its shielding effectiveness, there’s no complete measuring method andstandard at present. Therefore, the topic studies on the testing method of shieldingeffectiveness of electromagnetic shielding clothes, providing the scientific evidence forthe development of it, evaluation basis for its practical application and theoretical supportfor the corresponding standard-setting.The paper mainly studies on the measuring method of shielding effectiveness ofelectromagnetic shielding clothes. It establishes model of shielding effectivenesscalculation of the three-dimensional shielding clothes when human body in dress, putsforward the effective testing method that suits it and does the analogue simulation for thetesting system through three-dimensional electromagnetism simulation software from thefundamental of shielding electromagnetic wave of electromagnetic shielding clothes.Firstly, the paper analyzes the factors impacting the shielding effectiveness ofelectromagnetic shielding clothes from the point of view of humanbody-clothing-environment mainly including the electromagnetic wave frequency,electromagnetic radiation distance, clothing material characteristics, clothingthree-dimensional curved surface structure, the gap and holes on the clothes. Secondly, it discusses the shielding mechanism of electromagnetic shielding clothesin the state of actual dressing based on the morphological characteristics of human bodyand fundamental of its shielding electromagnetic wave. And it builds the calculationformulas of its shielding effectiveness under the condition of near-field and far-field incombination with main influence factors of its shielding effectiveness, drawing aconclusion that the calculation formulas contains electromagnetic wave parameter,electromagnetic radiation environment parameter and the parameter of clothes curvedsurface structure.Thirdly, the paper proposes the shielding effectiveness testing method ofelectromagnetic shielding clothes that suits human body-dressing-environmentalsystem---GTEM cell. It establishes the GTEM cell experimental measurement system ofelectromagnetic shielding clothes, sets up the automatic test experimental platform ofGTEM cell and analyzes in more details applicability and test range of GTEM cell fromthe test principle, equipment, environment and object. It comes to a conclusion thatGTEM cell method is simple and flexible, easy to be set up and has operation feasibility,controllable test result, advanced equipment, large testing range and low testing cost.Finally, the paper does the analogue simulation for the test process of GTEM cellthrough HFSS three-dimensional electromagnetism simulation software to analyzeshielding effectiveness result of partial electromagnetic shielding clothes, and then makea comparison experimental result with theoretical calculation, finally analyze the errorcause between theory and actual shielding effectiveness, further proving the GTEM cellrationality. And it reaches a conclusion that the shielding effectiveness value ofelectromagnetic shielding clothes will be much lower as the steradian value of dressingincreases in the same environment of electromagnetic radiation and as the radiationfrequency value increases under the environment of far-field radiation. The result that italso obtains is that experimental end value is close to that of theoretical calculation,slightly higher than it. These conclusions further prove that GTEM cell can effectivelytest the shielding effectiveness of electromagnetic shielding clothes in the actual dressingcondition.