The European Space Agency (ESA) and TNO are cooperating on a number of research projects for the demonstration of the performance and possibilities of new MMICs in Gallium-Nitride (GaN) technology. ESA is highly interested in this technology because of the robustness and high power capability
Currently the majority of the integrated circuits for microwave applications are designed in the mainstream semiconductor technology Gallium-Arsenide (GaAs). Compared to silicon this technology allows more power generation combined with higher operating frequencies. But since a few years a new "wide bandgap" semiconductor technology has been in development. This technology is based on the III-V material Gallium-Nitride (GaN). Compared to GaAs this technology offers even higher power density, combined with a high breakdown electric field. The high power density makes this technology very suited for realizing high power amplifiers. One of the first commercial applications is for use in base stations for telecommunication, but also application in radar systems is very interesting. Components based on this technology are currently introduced on the market, however further research and development for improvement and extension to higher frequencies is needed.
Because of the robust performance of the GaN technology ESA is very interested in learning the capabilities of this technology: MMIC designs for space applications must be able to withstand high temperatures, radiation and must be robust against large incoming signals. Therefore ESA has issued a number of tenders for projects to demonstrate the microwave capability of GaN MMICs, focusing on robust performance, power generation at millimeter wave frequencies, but also at the low-noise performance. TNO, in cooperation with European GaN suppliers such as United Monolithic Semiconductors (UMS), Fraunhofer IAF and the Ferdinand Braun Institute (FBH), has taken on this challenge to demonstrate new microwave designs in GaN technology, ranging from P-band (450 MHz) up to ongoing work at W-band (94 GHz).
Using the many years of MMIC power amplifier design experience, TNO has successfully demonstrated the power capability of GaN at Ka-band. A GaN power amplifier chip set (driver and high power amplifier) could replace the currently used traveling wave tubes, resulting is smaller and light weight solid state power amplifiers. Apart from use in power amplifiers TNO has also successfully demonstrated the performance of GaN technology for robust low noise amplifiers. The designs are capable of withstanding very large input powers without degradation of the performance or permanent damage. This development will lead to more robust receivers for space-based satellite communication equipment. Other research topics currently funded by ESA are the development of a robust solid state power amplifier at P-band (450 MHz) and L-band (1.5 GHz) and the demonstration of GaN power amplifier MMICs at millimeter wave frequencies (94 GHz)