Frequency-response variability of voltages induced by field-to-wire coupling in random bundles of twisted-wire pairs on-board small satellites

Procedures and results are reported for an experiment aimed at assessing noise induced by field coupling to a random bundle of twisted-wire pairs (TWPs) installed in a complex electromagnetic environment. The test case is representative of radiated-susceptibility phenomena occurring in aerospace systems such as satellite for scientific missions. In particular, the structure under analysis is composed of six randomly-bundled TWPs, excited by a nonuniform electromagnetic field generated by a monopole antenna inside the mock-up of a small-sized satellite, in the frequency range 250 MHz-1 GHz. Measurement is repeated for several hand-made samples of the bundle. It is shown that the common-mode and differential-mode voltages induced in terminal loads are characterized by high sensitivity (up to 40 dBs) to different bundle samples. By the light of experimental results, the weakness of deterministic and simplified field-to-wire coupling models is discussed.