Design and performance of the Transmit/Receive Module and the Tile Sub-System of Advanced Synthetic Aperture Radar (ASAR) for ENVISAT satellite

A major space-borne radar program is on-going in Europe : the Advanced Synthetic Aperture Radar supported by the European Space Agency. ASAR makes use of an active antenna composed of 20 RF Tile Sub-systems. Each Tile embeds 16 C-Band Transmit/Receive Modules, 1 Control Interface Unit, 4 Power Supply Units and 1 Radiating Panel. It is clear that the overall 320 T/R Module is the key element of the radar performance. Emphasis is put on the T/R Module design which is dual H/V polarization, 10 W transmit power, 3 dB receive noise figure and use both discrete FETs (P. HEMTs and Power GaAs FETs) and GaAs MMICs. Commands and DC supply switching are controlled with an integrated ASIC. Overall size is 213×38.4×22 mm3 and weight is 200 gr. In order to succeed the electrical challenge, new miniaturizing technics and technologies were qualified at space level as integrated MMIC functions, new RF substrate and connections and a lot of assembling processes. Due to the high volume production (more than 320 T/R Modules and 8000 hybrids) the design has been put through a very exhaustive industrialization procedure which is detailed below.