L-, S-, and C-Band EMI Measurement and Characterization of Spacecraft ESD Events

Abstract

Built upon existing electric thruster pulse emission research capabilities, time-domain techniques were employed to capture the electromagnetic interference (EMI) emission in simulated spacecraft electrostatic discharges. The test setup included custom-built four-channel data acquisition instrumentation anchored by a 15-GHz digital oscilloscope, and a dedicated fiberglass vacuum chamber inside a semianechoic shielded room. The test article was designed to simulate a solar cell array and was irradiated with an electron gun. Emission pulse waveforms and frequency spectra of EMI emission pulses obtained via Fourier transform are presented for both conducted and radiated emissions. Statistical analyses were made of the radiated emission of 100 discharge events each for eight experimental modes that varied electron gun potential from 10 to 20 kV and substrate bias conditions of 0 V, 5 kV, and floating for a normal gradient configuration. The peak of the amplitudes distributions were near 70, 60, and 50 dBìV/m/MHz for the L-, S-, and C-band, respectively, with maximum peak amplitudes of 80, 75, and 65 dBμV/m/MHz for these three bands.