Resonance absorption in single and cascaded lossy waveguide-dielectric resonators

An approximate theory of lossy waveguide‐dielectric resonators (WDRs) is developed. The theory is based on a search for the resonator's natural oscillations providing the required ratio between the radiation and intrinsic Q factors. This allows us to predict and control the level of absorbed power by changing the oscillation coupling or loss coefficient. The theory's limitations and validity are verified by a comparison with the exact numerical results obtained for the resonators, which are formed by rectangular dielectric posts and partially filled H‐plane stubs in a rectangular waveguide. Potential applications of the developed theory for the design of narrowband absorption filters are demonstrated. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 122–126, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10694