Incident Power Density of Electrically-Large Planar Phased Arrays Communicating with Non-Geostationary Satellites

The proliferation of planar phased array antennas that communicate with Low Earth Orbit (LEO) satellite constellations has unveiled potential measurement differences between fixed beam and scanning phased array antennas for assessing the time-averaged power density. Communicating with LEO satellites requires constant beam movement so exposure changes with time. Additionally, communications arrays, following Satellite Earth Stations and Systems (SES) regulations, are required to not transmit unless they are receiving enabling commands from a satellite - so blockages that stop communication and transmissions further reduce time-averaged power flux. These complex RF pattern, pointing and operational modes leads to a proposed introduction of a spatial duty cycle that weighs time-averaged power density by the proportion of time the beam is on a target area. This paper presents a method to characterize the time-average power density and exposure from electrically large-phased arrays used for commercial LEO satellite communications in the near- and far-field.