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UMS has developed an industrial power HBT process especially dedicated to power MMICs in the 10GHz frequency range. The process has been qualified and meets the very demanding specifications required for X-Band high power amplifiers. Aside from the obvious RF performances, this includes the demonstration of the necessary stability and reproducibility of the process, associated with state-of-art reliability. It is important to note that the later has been achieved without affecting the high frequency capability of the devices, and demonstrated directly on high power transistors. Thanks to its intrinsic qualities this process can naturally also be used for other applications, like low phase noise voltage controlled oscillators, and power amplifiers at lower frequencies (for mobile phones for instance).

The comparison of the linearity performance for three PHEMTs have been investigated in Ka band. The studied transistors are a single recessed PHEMT, a double recessed PHEMT and a double recessed dual channel PHEMT. The main result is : at a given output power level, the double recess allows a large improvement of the intermodulation ratio (IMR), thanks to its higher drain-source bias voltage capability, compared to the single recess. The second result is : the double recessed PHEMTs comparison shows that the dual channel, thanks to a more wide and uniform ransconductance distribution than the single channel, is a better solution for linearity application at 26GHz.

The APOS (Advanced Power Subassemblies project addresses the devices (MMIC or discrete) used in the solid state power amplifiers (SSPA) that drive the transmit active antenna. These are key devices and their electrical and thermal performances have a major impact on both the satellite and the ground terminals. GaAs-based heterostructure bipolar transistor, due to their superior power/linearity performance, could be one of these enabling devices. This aspect will be addressed within the frame of this project through three main objectives : 1)To analyse the reliability of UMS HBT technology and demonstrate it meets the requirements of the commercial satellite markets. 2)To improve the power and thermal performances of HBT by developing a power flip- chip assembly technology using thermal bumps in the active area of the power device. 3)To benchmark the developed power HBT technology by using the power MMIC in a suitable active antenna module. This project consortium is formed by Alcatel Space, that will co-ordinate the project, United Monolithic Semiconductors (UMS), Thomson-CSF, Institute for Material Research at Limburg University Centrum (1MO-LUC), DESTIN and Institut d'Electronique et de Microelectronique du Nord (1EMN).

The development of a highly integrated Ka-band (24-26GHz) transceiver module for a high volume point to multipoint telecommunication application is presented. In order to reduce the costs, a full GaAs MMIC solution has been chosen. The module architecture and assembly technology are described. 8 different Ka-band MMICs have been or are being designed and fabricated for this application. The measured performances of the developed MMICs and of the module prototypes are given.