On the Maximum Expected Electric Field in Electrically Small, Undermoded Enclosures

Bremner, P G ; Trout, D H ; Vazquez, G

关键词: AEROSPACE INDUSTRY;    AVIONICS;    CAVITIES;    ELECTRIC FIELDS;    ELECTROMAGNETIC COMPATIBILITY;    ENCLOSURE;    FREQUENCY RANGES;    MATHEMATICAL MODELS;    MEAN SQUARE VALUES;    MODE (STATISTICS);    PROBABILITY THEORY;    RESONANT FREQUENCIES;    REVERBERATION CHAMBERS;    SHIELDING;   

RP-ID  :  KSC-E-DAA-TN61816

学科分类：统计和概率

美国|英语

来源: NASA Technical Reports Server

【 摘 要 】

This paper reports the experimental validation of an improved statistical model for the prediction of maximum expected electric field in electrically small and under-moded enclosures. The aerospace community is interested in application of Hill’s statistical models to design of avionics boxes for shielding effectiveness and for tailoring EMC test requirements for critical applications. However, it is observed that the probability distribution for mean-squared electric field (|E(sub x)|(exp 2)) in an electrically small enclosure differs from the exponential distribution which is widely used in reverberation chamber testing. It is postulated here that the difference is attributable to the under-moded character of the small enclosure. We will define “under-moded” as the condition where a single excitation frequency does not excite enough closely spaced resonant modes to achieve Hill’s assumption of an isotropic (or fully diffuse) plane wave field in the enclosure.