Jean-François Villemazet

New Wide Band Predistortion Linearizer with an Advanced Shape Tuning Capability for Space Applications

This paper proposes a new predistortion linearizer architecture allowing a new advanced shape tuning capability in addition to the classical magnitude control of the gain expansion and phase shift. This new feature is compatible with a wide band operation. A frequency bandwidth of 1.8 GHz has been demonstrated with a Ku-band TWTA between 10.95 and 12.75 GHz. A C/I3 improvement of about 20 dB at -6 dB IBO per carrier and a NPR increase of 7 dB at -6 dB IBO were obtained thanks to this new linearizer circuit with regard to a conventional diode predistortion linearizer.

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.

New compact double balanced monolithic down-converter application to a single chip MMIC receiver for satellite equipment

This paper proposes a new compact double balanced mixer architecture suitable for a satellite repeater. The size of the proposed mixer has been divided by more than 5 compared to the previous generation currently used in the 14/12 GHz satellite repeaters. Thanks to its small size, about 1 mm/sup 2/, this mixer was integrated in a single chip MMIC receiver, including 5 different functions.

Low cost MMIC chipset for VSAT ground terminals

This paper presents results of a Ka-band VSAT ground terminal MMIC chipset developed in a cost reduction context. The first one, a low level multifunction designed for up-conversion with high gain driver, exhibits a 17dB conversion gain with an associated P/sub 1dB/ output power close to +18dBm. The second one, a high power amplifier with embedded power detection, delivers 2W RF output power associated with 24dB of linear gain. This chipset combines performance, integration and low cost.

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.

New Analog Predistortion Linearizer for Ku-band TWTA allowing 1GHz Instantaneous Wide-Band Satellite Operation

This paper proposes a new wideband predistortion linearizer for TWTA enabling to use broadband multi-carrier signals for the new Telecom satellite transmit sections. The linearizer has been embedded in a channel amplifier equipment and successfully tested with a wideband Ku-band TWTA. A state-of-the-art NPR performance was obtained over the entire 10.7–12.75GHz Ku-band with multi-carrier signals up to 1GHz instantaneous bandwidth.