HOM damping with coaxial dampers in a pillbox cavity without the fundamental mode frequency rejection filter.

摘要

Coaxial dampers with E-probe and H-loop couplers are used to damp higher-order mode (HOM) in an 840-MHz cylindrical prototype cavity. The dampers are positioned to have minimum coupling at the fundamental frequency, f(sub 0), without using any blocking circuit. The E-probe dampers are used at the equatorial plane of the cavity. The H-loop dampers are used in the end wall of the cavity. The fundamental mode decoupling can be done by positioning the loop plane in the direction of the H-field of the mode. For both dampers, the fundamental mode coupling can be better than (minus)50 dB. The damper load resistance is varied to find the optimum loading. Measurement is made for three cases with (1) three E-probe dampers, (2) three H-loop dampers, and (3) three E-probe and three H-loop dampers.