Motors could be redundant on space-borne radiometers

A new way to eliminate the need for motors in space-borne radiometers has been devised by researchers at Queen’s University Belfast.

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.

According to the researchers, the result of replacing the motor with liquid crystal is a 10 per cent weight saving per radiometer and therefore there is a reduction in the overall amount of power required.

The researchers claim the new technology could also eradicate the drop-off of mobile phone signals passing through energy-efficient glass and, in theory, create buildings that can be locked down to block radio signals at the flick of a switch.

The project has attracted funding of £500,000 from the European Space Agency (ESA) and £100,000 from economic development agency Invest Northern Ireland.

The devices are expected to be used in space missions from 2025 onwards if the prototype models are successful.