EMI in orbiting sounding radar from ripple in solar arrays

Electromagnetic compatibility (EMC) of DC/DC converters is discussed in the specific context of satellite missions for remote sensing, where low-frequency radar are used to characterise subsurface layering in planetary bodies like Mars, Venus, Europa. The operating frequency range of these instruments extends down to 100 kHz, and may include switching frequency of the power conversion units aboard spacecraft. So, relevant conducted electromagnetic interference (EMI) may be produced when electromagnetic fields associated to the current fluctuations in solar arrays, related to operation of the switching DC/DC converters, are coupled to radar antennas. In this work we discuss the low-frequency EMI phenomenon, in terms of the related reduction of dynamic range in spaceborne radar systems. We also discuss the effectiveness of some filtering approaches to be used in order to attenuate radio-frequency (RF) signals in the solar array power lines is also discussed in the specific context, taking into account the trade-offs involved with weight and volume constraints, typical of space applications.