Design and Thermal Analysis of a Coupled-By-Rods Interaction Structure for Traveling-Wave Tubes

The design and thermal performance of a coupled-by-rods interaction structure for coupled-cavity traveling-wave tubes (TWTs) is presented in this paper. The device features a new slot configuration consisting of a circular hole comprising of a metallic rod passing through it. This particular slot has been designed in order to allow a better thermal behavior, while maintaining comparable electrical performances to already known structures. The small dimension of the slot enables a more efficient heat dissipation, while the metallic rod ensures the magnetic coupling between the cavities. An X-band coupled cavity TWT making use of this new slot design has been simulated and compared to a conventional staggered slot structure. The coupled-by-rods structure has been capable of reaching a value of 13 kW of saturated output power, comparable to a conventional counterpart, and it exhibits a saturation temperature 75°C lower when compared to a conventional configuration.