The Chirp Up-Converter and Amplifier (CUCA) for the ERS-1 Radar Altimeter

The paper describes the microwave signal processor under development for the transmitting chain of the radar altimeter to be placed on board the ERS-1 remote sensing satellite. The unit is fed by 450 MHz and 7.35 GHz signals coming from the radar chirp generator and frequency generator; it provides 13.8 GHz outputs to the HPA and to the receiver LO port. Functions performed are: up-conversion from 450 MHz to 6.9 GHz: filtering and amplification at 6.9 GHz: bandwidth expansion by frequency doubling to 13.8 GHz and filtering: pulse modulation and amplification at 13.8 GHz. Design solutions and attained performance are described.