There is an increasing need for high power microwave sources. Among this class of sources, Traveling Wave Tube Amplifiers (TWTA) are attractive for high power applications such for radars and long range satellite communications systems. Several important factors influence the performance of TWTs. Among them are: a suitable Slow Wave Structure (SWS) within the tube, beam focusing, attenuation, electron beam to wave interaction, collector module, and cooling efficiency. At the meeting several factors will be considered in addressing the issues relating to reflection, interaction with electron beam, support layout etc. The typical challenges are: · Reflection of the backward wave is a major concern as it diminishes forward gain greatly. A good attenuator circuit is also necessary to absorb reflections due to impedance mismatches and space charge waves. · Interaction with the relativistic electron beam is crucial for high power TWTs. Specifically, high phase velocity in the RF wave worsens the coupling. As a result, a longer tube is needed for stronger interaction, implying difficulty with its miniaturization. · A good support of the slow wave structure is also needed inside the TWT. Traditionally, dielectric materials were used to slow down waves and provide non-conducting contact between the SWS and waveguide wall. But dielectrics also scale down the electron beam velocity, implying smaller saturated powers. Thus, a suitable support layout is needed to also maintain high power characteristics.