Experimental results of plasma induced EMI effects in a reflector antenna system

This paper presents measurement results of the electromagnetic interference (EMI) caused by the plasma plume of ion thrusters firing through the RF beam of reflector antennas. The EMI effect consists mainly in the introduction of discrete spurious modulation products on the RF carrier thus degrading spectral purity. The measurements were carried out on a mockup which is geometrically representative of the actual SGEO spacecraft design. The mockup and the acquisition system were specifically designed to allow RF measurements inside a metallic vacuum chamber. Three ion thrusters were characterised during the test campaign: SPT-100, HEMP-T, PPS-1350.