Eigenvalues and ohmic losses in a disc-loaded coaxial cylindrical waveguiding structure for MILO

Abstract

A metal disc-loaded coaxial cylindrical waveguiding structure was field-analyzed using the modal matching technique with due care to include all the harmonics of the structure by authors previously. For the slow-wave TM mode of operation, the field expressions were substituted into the structure boundary conditions to write a set of equations in field constants. The condition of the non-trivial solution of this set of equations yielded the dispersion relation of the structure. The analysis was extended further to estimate the structure ohmic power loss due to the finite conductivity of the structure material, which limits the power handling capability for its application in the high power devices, like the MILO. The structure field constant, occurring in the analytical expressions for the ohmic power loss has been obtained by normalizing the RF fields using the orthonormality property. Further, the structure has been simulated using the commercial code, 'CST Microwave Studio'. The simulated values have been found to be in agreement with the developed analytical results. Furthermore, this structure has been numerically appreciated over a wide range of structure parameters and the role of the individual parameters on the structure characteristics has been studied. It is hoped that the present study would help the MILO designers in optimizing its structure parameters keeping the structure losses within the desired limit. © 2012 ISRAMT.