Proba-V’s X-band communication system will include an extra amplifier based on novel gallium nitride technology instead of standard gallium arsenide. Already in everyday use within light-emitting diodes – lighting up Buckingham Palace among other spotlit landmarks – GaN is attracting great interest within the world of integrated circuits.
ESA has identified GaN as a key enabling technology for space: its high power capacity makes it the most promising semiconductor since silicon. GaN operates reliably at much higher voltages and temperatures than silicon or gallium arsenide, offering a five- to ten-fold increase in communications signal strength without requiring active cooling systems. As an additional advantage for space missions, it is also inherently radiation resistant.
The X-band transmitter is produced by Syrlinks in France, with the GaN amplifier coming from TESAT in Germany. This amplifier is among the earliest outputs of an ESA-led European consortium to manufacture high-quality GaN devices for space uses: the ‘GaN Reliability Enhancement and Technology Transfer Initiative’ (GREAT2). This novel amplifier also has an adjustable power output, so its use should help to conserve the small satellite’s power consumption while also providing extra redundancy.