Experimental analysis for the optimal choice of high-order modes couplers design parameters for resonance damping

The paper describes an experimental analysis for the definition of the design parameters of High-order Modes couplers, used to damp electromagnetic resonances in an equipment. The experimental analysis consists of the characterization of an RF equipment alone and with the insertion of High-Order Modes (HOM) couplers of different lengths and diameters. The analysis has been applied to a test equipment at the European Organization for Nuclear Research (CERN), where a significant reduction of the resonance has been obtained for certain configurations of the design parameters. In the paper, the full method is explained: the theoretical idea, the measurement approach, and the experimental results.