183GHz Cavity-Backed Spiral Radiometer Antenna with Dual Circular Polarization for Earth Observation Applications

New radiometer technology is a key enabling factor for the upcoming new generation of space missions; earth observation applications, with the use of cubesats and nanosatellites, will benefit greatly from the insight into our own planet these sensors can offer. In this paper, a four-armed cavity-backed radiometer spiral antenna is designed and simulated to capture the $183\text{GHz}\pm 5\text{GHz}$ water absorption line, fundamental for measuring moisture levels in the atmosphere and evaluating the effects of climate change in our planet. Due to the manufacturing difficulties involved, a scaled design centered in 7GHz is also provided. This scaled design is manufactured and measured as a way to validate the EHF design.