Space radiation hardness of PTFE based RF substrates for GEO satellite application

RF substrates based on PTFE are often used in high frequency space circuits. As they are mounted inside of an enclosure, the body of the satellite and the housing absorbs space radiation. However, patch antennas in space applications impede shielding of the active substrate area resulting in the exposure of the PTFE substrate to high dose space radiation. This paper shows the results of a measurement campaign to determine the radiation hardness of the most used PTFE based RF substrates in space applications. The simulated exposure was 15 years in geostationary orbit using a Cobalt 60 source. Consecutive intermediate measurements of the input reflection coefficient and the far-field radiation pattern have been executed to quantify the effects of space radiation.