High power EIK amplifier for interferometric space-borne applications

For the proposed Surface Water and Ocean Topography (SWOT) Mission, NASA-JPL would require pulsed High Power Amplifiers (HPAs) with 1500W minimum output power at 35.75 GHz. The duty factor of the HPA can be as high as 8.5%. An Extended Interaction Klystron (EIK) was chosen for this application and a High Voltage Power Supply (HVPS) effort was initiated to support the EIK. The HPA proposed for SWOT represents challenges to the EIK and HPA team. The average RF power is four times higher than that of the CloudSat Mission´s EIK-based HPA, while bandwidth of over 0.5% with exceptional flatness is required. The coherence requirements of the proposed interferometer would impose strict phase and amplitude stability requirements on the HPA. In this paper the authors present the design trade decisions that would be implemented to address those challenges.