A simple procedure for impedance matching and tuning of microwave couplers for an electron linear accelerator

A simple experimental procedure to match and tune "door-knob"-type microwave couplers is presented in this paper. The procedure is suitable for accelerating structures with both input and output couplers and allows a fast convergence to the minimum reflection condition for a cavity coupler with fixed phase shift. The standing-wave ratio and the coupling cavity phase shift as functions of the coupler dimensions and frequency are also reported.