Impacts of cubic Boron Nitride (CBN) support rods on TWT performance

We propose new support rod material in helix TWTs to improve the heat dissipation performance of the tubes, which is the cubic Boron Nitride (CBN) crystal with the second highest thermal conductivity and relatively low dielectric constant. The high frequency characteristics and the beam-wave interaction of helix slow wave structure with CBN and BeO support rods are simulated and analyzed, respectively. The results show that the difference between saturated output powers is less than 10%, and backward wave oscillation power hole still exists. Temperature distribution on a TWT with CBN support rod is also obtained with lower temperature than one with BeO rods. CBN can be made as support rods of TWT with high heat dissipation capability.