Coupling to aerospace cables at microwave frequencies

The ability to design electronic systems which will survive in high power radiated environments requires techniques for predicting and evaluating the coupling from the radiated field to the circuits and components which are susceptible. Efforts to develop these techniques at McDonnell Douglas have resulted in an approach which divides the RF coupling problem into two parts: effective aperture of the unshielded cable, and shielding effectiveness of the cable and/or enclosure shielding. The key to the approach is an accurate method of determining shielding effectiveness of configurations too complex for analytical solutions. To test the approach, data have been processed from a large number of anechoic chamber measurements at 3.0, 5.6, and 9.1 GHz for shielded and unshielded twisted wire pairs both alone and inside enclosure with various discontinuities. It is shown that MIL-STD-1377 provides a method for accurately measuring the reduction in RF pickup provided by cable shielding.