Lumped parameters for re-entrant resonators

Abstract

The paper shows how the resonant frequencies and the Q factors of re-entrant cavities of cylindrical and square symmetry can be calculated by the use of a simple L-C equivalent circuit. In the case of re-entrant cavities of cylindrical symmetry the comparison with the data reported in literature gives an average agreement of the order of 2.3%. To test the computational method in different geometries, six prototypes of square symmetry re-entrant resonators in a frequency range between 2 and 4 GHz have been constructed. In this case the average matching between the measured values of the resonant frequency and the theoretical ones was of 1.4%.