A fresh look: a more economic approach to HIRF certification

An in-depth review of electromagnetic aircraft coupling models and recent experimental results from 1984 to 1995 provides a systematic approach for conducting HIRF certification. This approach uses models developed by NIST and LLNL to characterize the internal HIRF environment of an aircraft. Recent measurements on 707, 757, and GA/business aircraft conducted by NSWC, NIST, LLNL, and AF Phillips Labs suggest ways to reduce the dimensions of the test space. The principle dimension of this approach is frequency. Analysis is used to predict the expected fields in each of three frequency regimes where the coupling phenomena are unique. Analysis and spot testing can be used to eliminate or reduce the required testing in each of these ranges. Considerable savings in test time, complexity and costs can be achieved by collapsing the remaining dimensions of power density and illumination. Specifically, equivalent internal illumination by much lower power sources can be substituted for high powered external illumination. The number and choices of polarization and required aspect angles can be reduced as well using this approach.