Space Applications Centre (SAC) is dealing with wide variety of activities from payload development to societal applications and is responsible for the development, realisation and qualification of communication, navigation, earth observation and planetary payloads. One of the priorities of the Centre is to develop and promote crucial technologies that lead to self-reliance of Indian space programme.

Traveling Wave Tube Amplifiers (TWTA) are commonly used in satellite communication links, earth observation payloads, scientific missions or probes, inter-spacecraft communications links etc. The TWTA consists of Electronic Power Conditioner (EPC) and Traveling Wave Tube (TWT). The TWT is a complex multidisciplinary technology involving controlled interaction of microwave with electron beam under ultra high vacuum. The criticality of TWT realisation can be gauged by the fact that every single TWT involves defect free realisation of over 300 small precise piece parts and more than 260 leak proof joints. This also involves handling of the DC voltages of the order of 6 KV. TWTA is one of the integral parts of all communication payloads. Hence, their dimensions, mass and efficiency are major contributors to the satellite’s power budget and require special attention. The Bharat Electronics Limited (BEL) Bengaluru has supported the fabrication and assembly of TWT.

SAC has developed space qualified C-Band TWTA for space borne applications, jointly with Central Electronics Engineering Research Institute (CEERI), Pilani. Qualification involves testing of fragile TWTA for severe vibration withstanding capability, which is critical during rocket launch and also satisfactory stable performance during thermal vacuum condition. Care needs to be taken that it is not affecting the performance of other payload subsystems with its electromagnetic interference, as it is very high power subsystem.

After the completion of development of space qualified C-Band TWTA, the initiative to develop the Ku-Band Short Length TWT was undertaken jointly with CEERI. Due to the requirement of large number of such devices, indigenous development can significantly reduce the dependency on foreign sources. This significant milestone will pave the way for space qualification and indigenous realisation of Ku-Band TWTA. Further, it will be integrated with indigenously developed High Voltage EPC and Solid-state amplifier to complete it as Microwave Power Module (MPM).

Ku-Band Short Length TWT (Proto-type)

CEERI handing over the Proto Unit to Director, SAC