C. Schaffauser

Prospective and issues for GaN microwave electronics into space satellites

On the very last months, gallium nitride (GaN) technology has made a remarked breakthrough in the world of microwave electronics with the announcement of commercially available power transistors. Those striking news follow several publicized results that had been published since few years. How this GaN technology would impact space- borne units is now a priority concern. Although the power capability of GaN technology is the first obvious profit, GaN could also be used for other applications like low noise amplifiers, mixers and probably more. The high sustainable temperature of GaN transistors is most striking advantage for in-flight use. This is connected to packaging design which is also experiencing a lot of activities and quick progresses. Of course, space application is dependent upon the full demonstration of reliability and this constitutes another field of investigation. Finally, our very first, promising, experimental results are presented: they open wide the road a revolution inside space-borne electronics: the rise of GaN.

Optimised thermal and microwave packaging for wide-band gap transistors : diamond & flip chip

Wide-band gap (WBG) transistors give a real breakthrough for power devices compared to silicon (Si) and gallium arsenide (GaAs) components. However, for space applications, the high power density of WBG transistors makes the thermal management critical and requires thermal investigations. Some packaging solutions dedicated to those power transistors are presented in this paper. The focus is made on diamond-based packaging with two topologies. In the first one, the die is soldered on a diamond carrier. In the second one, it is flip chip bonded on a diamond circuit. Thermal simulations, thermal cycling and electrical measurement results are given for both configurations.

A comparative study of different microstrip planar bandpass filters topologies in an industrial context

One of the most stringent specification in modern microwave equipment is the control of spurious levels. This is a daily concern for microwave engineers designing telecommunication or observation space-borne equipment. AAS- F has studied and developed planar bandpass filters in microstrip mode because they can be easily inserted into hybrids. The investigated filters topologies are coupled lines, interdigitated, hairpin, pseudo-elliptic response and dual behaviour resonator. each of them has advantages and drawbacks, first in term of electrical response but also in term of industrial effective use. For each topology, a list of main characteristics has been identified to allow comparison and easier choice, depending of the targeted application. This includes the reachable bandwidth, the insertion losses or the synthesis easiness. Also, the filters sensitivity to mechanical environment or manufacturing process have been summarized in a handful way. Such a study can give precious inputs for designers in other microwave domains as well.

Use of RF MEMS and micromachined parts to realize highly integrated V band active feed for satellite antennas

Micromachining and microelectromechanical systems (MEMS) technologies can play a key role in miniaturization of satellite antenna front-ends. Alcatel Alenia Space France has demonstrated for the first time the operation of a V band integrated active feed combining 3D stacking concepts and micromachining technologies. The realized integrated module size is 35 times 35 mm2 with a thickness of 7 mm including miniaturized DC and RF connectors. In this paper, we present the latest test results obtained on this MEMS based active antenna