Digital receiver for radiometers
The objective is to design and breadboard highly integrated microwave receiver function based on the use of novel European processes for EO applications.
The mixed signal (SiGe BiCMOS) technologies have been under interest in the specific area of signal generation due to good achievable signal quality. Meanwhile, the technology has been improved to reach higher operating frequencies and lower noise figures, too. The SiGe is very well suited for digital receiver implementation at L-band.The advantage of SiGe over GaAs in space use is foreseen in the high degree of integration due to the feasibility of mixing analogue and digital functions on a single chip. This means that the complete microwave system (e.g. receiver) can be implemented in a volume that is a fraction of the volume needed in a GaAs-based system where hybrid implementation is required. The power consumption would also be lowered in a single chip solution in comparison with the GaAs-hybrids. SiGe can have substantial potential in low-power applications that need a number of highly integrated receivers. For example, for the Soil Moisture and Ocean Salinity (SMOS) mission, the number of hybrid receivers had to be reduced due to mass constraints which led to compromised system performance. The digital concept will also facilitate new functionalities in interference detection and mitigation. The need for effective mitigation is evidenced by early observations by SMOS. This activity aims at design, manufacturing and test of a highly integrated digital receiver at L-band with digital output interface. In addition to direct L-band operation, the receiver lends itself as a building block (IF stage) for higher mm-wave heterodyne receivers. The development will support highly integrated synthetic aperture receivers with interference detection and mitigation, and the next generation of Sentinel-3 radiometer. A receiver-on-chip shall be targeted if it is justified.