Motors could be redundant on space-borne radiometers

Researchers at the Institute of Electronics, Communications and IT (ECIT) and the Northern Ireland Semiconductor Research Centre (NISRC) claim that by incorporating liquid crystals in their frequency selective surface (FSS) antenna rays, they can make motors redundant. 

The liquid crystals are sandwiched in between the FSS’s metallised quartz layers to act as an electronically controlled shutter. Applying a small voltage to the structure enables the radiometer to be switched from calibration mode to signal-detection mode without mechanical components.

Raymond Dickie, a senior engineer working on the project, said: ‘Motors are used on radiometers’ instruments to mechanically scan the dish antenna, pointing it at the Earth and onboard calibration targets. Liquid crystal incorporated into frequency selective surfaces and reflectarrays have the potential to replace the mechanical scanning mechanism.’

Current generation remote-sensing radiometers that collect this data incorporate a turntable-mounted mirror operated by an electric motor to calibrate the instrument before each scan by directing their field of view between cold and ambient targets.