Marziale Feudale

GaN for space application: almost ready for flight

On the last years, gallium nitride (GaN) technology has made a remarked breakthrough in the world of microwave electronics. Power transistors are now available. 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, after 8 years of GaN studies, experimental results are presented: they open wide the road a revolution inside space-borne electronics: the rise of GaN.

A C-band GaAs-pHEMT MMIC low phase noise VCO for space applications using a new cyclostationary nonlinear noise model

This paper describes the design and implementation of a C-band MMIC VCO developed in the framework of activities oriented to the improvement of products for space applications. The circuit exploits a single device with a microstrip integrated resonator coupled with varactors. The exploited technology is a space-qualified GaAs 0.25-um pHEMT process. The MMIC exhibits 350-MHz bandwidth at 7.3 GHz, with 14 dBm output power and −86 dBc/Hz single side-band phase noise at 100 kHz from the carrier. Measured performances are in good agreement with simulations. The active device adopted for the design was characterized in terms of both low-frequency noise in quiescent bias-dependent operation and its up-conversion into phase noise under large-signal RF oscillating conditions, using in-house developed measurement setups. A new compact nonlinear noise model was identified, implemented and exploited for phase noise simulations. The model features cyclostationary equivalent noise generators. Comparisons between measurements and simulations show that the nonlinear cyclostationary modeling approach is more accurate than conventional noise models in oscillator phase noise analyses of pHEMT based circuits.

10 Watt High Efficiency GaAs MMIC Power Amplifier for Space Applications

This paper describes the design of a GaAs monolithic high power amplifier at Ku band. The chip delivers about 40 dBm of saturated output power, in CW operating conditions, at 11.7 GHz central frequency, with 17% of bandwidth. The saturated power gain is 12.4 dB with 2 dB gain flatness across the application bandwidth while the chip power added efficiency is estimated between 33% to 47%. The amplifier is designed to be used as final stage of a downlink satellite transmitter for Tracking Telemetry & Command system. A commercial power p-HEMT process capable of handling a power density higher than 1 W/mm has been selected for the MMIC design. Due to the space application, special attention must be put on the process and MMIC reliability: to this aim performances must be guaranteed in de-rated conditions respect to the process maximum ratings and, in addition, the channel temperature of the active devices must be kept within the value established by Space Requirements and carefully controlled. This makes the design objective very tight. The MMIC power amplifier design and some measurement results are presented in the paper.

Hybrid High Power Amplifiers for L-Band Space Application

This paper describes the design and implementation of 2 hybrid high power amplifiers at L band for a space application. Indeed, the amplifiers represent prototype test vehicles for a larger hybrid amplifier to be used as the final power stage in the transmitting chain of a T/R module of an L-band SAR antenna for earth observation. The amplifiers described in this paper exploit a discrete bar of a commercial 0.35 mum pHEMT process as active device. The first amplifier, featuring a single discrete device, delivers 12 Watts with 56.5% PAE and 12.3 dB gain at 2 dB compression. The second amplifier exploits 4 discrete pHEMT bars using input/output microstrip splitter/combiner and lumped wire bonding/ceramic MIM capacitor output matching networks. It delivers 42 watts with 50% PAE and 13 dB gain at 2.5 dB compression. Since it is a space application, these performances have been achieved with the required de-rating on break-down voltages, current densities and operating channel temperature. The latter has been evaluated by means of a 3-D device model implemented in the framework of a finite differences numerical thermal simulator. In spite of the constraints due to space de-rating rules, the obtained output power densities are 1 W/mm and 0.875 W/mm for the single-discrete and the 4-discrete amplifiers, respectively, which represent a value very close to the state of the art for pHEMT processes.

Applications of HEMT devices in space communication systems and equipment: a European perspective

Abstract In the last years the satellite applications have seen a strong increase in the space hardware demand mainly for commercial communication services like fixed satellite service (FSS), broadcasting satellite service (BSS) and mobile satellite service (MSS). The new boundary will be the low cost, high production rate hardware needed for satellite constellations like Teledesic and for multimedia satellite-based systems (Euroskyway, Spaceway, Astrolink, Cyberstar). The design and development of microwave and millimeter wave equipment has been deeply modified in order to combine technical requirements and market needs (large productions, low cost and fast lead time). In this scenario the maturity of gallium arsenide MESFET and PHEMT devices and processes for space applications is a key factor and the design and integration of GaAs MMICs is mandatory to achieve the mentioned industrial drivers in the space companies. The paper will focus the application of GaAs MMIC technology in the European space industry taking as reference the space production done by Alenia Aerospazio in Italy and other European space companies and providing a future road map.

Application of MMIC and ASIC technology to a new generation of satellite repeater equipment

This paperfocuses on Xth application of state-of-the-art technologies such as GaAs MMIC and ASIC in the development of a new generation of miniaturised microwave equipment for on-board satellite telecommunications repeaters.

Wideband Gap devices and technologies in the evolution of future space systems

This paper analyzes the possible and effective use of Wide Band Gap based devices in Space Equipment. An overview of the main applications is reported together with the status of main developments currently running trough different collaborations with research centers and Space Agencies. Reliability status is also mentioned with an short overview of recent results. Finally future trend are reported considering the possible evolution of the technology itself in the next years.

A method to design MMICs for high production yields

In this paper, a MMIC (monolithic microwave integrated circuit) design technique, oriented to the optimization of the production yields, is illustrated. This method, based on a sensitivity analysis, i.e. on the circuit behavior for variations of passive elements from their nominal value, and on the contemporary determination of the production yields, allows the identification of the circuit elements to obtain high production yield. Moreover it allows an appropriate choice of the circuit topology. As an example, this technique has been applied to design a MMIC to be employed on equipment where a high number of devices is required.

Fully Integrated Ka/K Band Hermetic Receiver Module

This paper presents an Engineering Model of a fully integrated, hermetic receiver as developed for commercial space flight applications. Repeatable performance especially at K band frequencies is difficult and costly in a production environment. State-of-the-art packaging technology and a family of dedicated MMICs were employed in order to guarantee performance as well as reduce production and alignment costs. This combined with Alenia Spazios extensive, flight proven heritage, has produced a receiver aimed at both the transparent and regenerative payload markets.

Ka Band MMIC Based Channel Amplifier for Commercial Satellite Applications

This paper describes the design and development of channel amplifier and lineariser functions for Ka band satellite payloads. The units combine the latest expertise in electrical design and technological implementation. GaAs MMIC technology is used to realise all the functions needed in the microwave section while advanced packaging techniques, such as low temperature cofiring ceramic, are employed to obtain a very compact and lightweight design.