Realization of a 36-way cavity RF combiner at 476MHz for IR-FEL

A 36-way cavity combiner was realized. The combiner structure is consisting of a cylindrical cavity; RF post-couplers, 36 nos., connected to N-type input ports; and a 1⅝" EIA coaxial combiner output port & coupler. Distinctive feature of this structure is that of inputs which are conductively coupled to the cavity; providing perfect symmetry for in-phase excitation, structural stability for its long term performance and that facilitating a large numbers of RF inputs to be combined. Design, construction, simulation and test results for its satisfactory performance are described for the cavity combiner which is to be used in combining output power from transistor based pulsed RF amplifier modules at 476MHz operating RF frequency so as to have 20kW pulse RF power source for IR-FEL.