INVESTIGATION OF A CIRCULAR RESONATOR WITH A HELIX OF NONUNIFORM DIAMETER

The operation modes of a circular resonator with a helix inside are in vestigated in this short paper. Considering the assumption that the ta pe current of the helix can be expanded into a Fourier series, the pro pagation constant of the infinite helix-filled guide is obtained by us ing the transverse boundary condition. The resonance impedance conditi on of the longitudinal direction is used to determine the operation mo des. The operation modes are determined to HEn1h, where h is an intege r denoting the rank of the roots of characteristic equation. The domin ant operation mode is proved to be the HE011 mode. Agreement between t he numerical calculated results and experimental values presented earl ier for a resonator with a helix or a tapered helix is obtained. (C) 1 998 John Wiley & Sons, Inc.