Multisection frequency filter consisting of a series of cylindrical resonators loaded with ring gratings

The problem of diffraction of cylindrical TEon‐wave on an axial‐symmetric series of N identical inhomogeneous resonators and sections of uniform waveguide is solved by the methods of theory of circuits and matrix functions. The resonator's internal region contains three magnetodielectric layers and a dense grating of conducting rings. The frequency and interference dependencies of the scattered field amplitudes and their dynamics are determined in the cases of strong and weak coupling between the resonators, single‐mode and multi‐mode bands, and high power density at the peripheric region. A correlation between the frequency dependence of the investigated filter and the pass bands of its infinite analogue's eigenwaves are established. The mechanism of exciting super‐high‐Q resonance oscillations absolutely transparent with loss‐free systems is analyzed. A model of the frequency filter with non‐mechanical control is proposed. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 87–90, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10524