The objective of the activity was to design, manufacture and test an EM of an EPC for Very High Power S-band TWT targeting 500 W RF power for the TWT. In the frame of the activity the TWTA integration and test was introduced via CCN. In the frame of this CCN the BB EPC was tested together with the BB TWT. Later on the EM EPC was integrated and tested with the same BB TWT.
S-band Mobile Broadcasting Satellites as Sirius and XM Radio for Digital Audio Broadcasting over North America, the Japanese-Korean MBSAT and the planned European S-DMB Eutelsat W2A for multimedia applications require very high EIRPs to guarantee a link to low gain user terminals. However, the maximum RF output power reached by state-of- the-art S-band TWTs is not higher than 250 W, one order of magnitude below the requirements of both digital radio and multimedia broadcasting satellites (up to almost 4 KW, depending on the application).
The TWTA is made up of two units: The travelling wave tube (TWT) as power amplifier and the electronic power conditioner (EPC), which adapts the main bus supply to the TWT. Moreover, in many applications a lineariser is required to compensate for the non-linearity of the TWT. On the TESAT design a linearised channel amplifier (LCAMP) can be included in the EPC and forms a so-called MPM.
In this project the EPC was developed by Tesat. The TWT had been developed by Thales in a separate ESA Artes program.
The TWT together with the EPC forms the TWTA (Travelling Wave Tube Amplifier)
The activities in this study were divided into two Phases.
In a first phase investigations of new EPC technologies and design in order to meet the requirements of a new very high power S-band TWT targeting 500 W RF power have been performed. This phase included interactive discussion with the TWT manufacturers and a first outline of a design specification.
In a second phase a breadboard has been built for evaluation of new technology items and the design has been validated by incorporation in a very high power S-band EPC. The breadboard activity was followed by the design, manufacturing and test of a very high power S-band EPC, including necessary baseline analysis and documentation according to an EM standard. The design considers the latest status of the very high power S-band TWT development and the adaptation of the actual technical requirements.