Review of different ring resonator coupling methods

Microstrip ring resonators can be applied in microwave filters and oscillators as well as in their original role as tools for dielectric material characterisation. They have been widely used in satellite broadcast reception systems, military facilities, base stations, radar detectors, wireless mobile communications, telecommunications computer systems, PCS/PCN filters, microwave, modern medicine and many other areas.In the absence of open ends, ring resonators have a distinctive low radiation loss when comparing to other microwave resonators. They can be practically implemented rather easily and can be realised as simple structures. This paper deals with the design of a simple ring resonator including the design and implementation of a simulation model for the review of different ring resonator coupling techniques: the Loose-coupling, the Enhanced-coupling and final the Matched-stub-coupling technique. Finally, a comparison among the developed simulation models was performed in order to evaluate each technique and conclusions were extracted.