On the Study of Resonance Splitting in Microstrip Ring Resonators

An equivalent circuit model based on transmission line theory has been analysed to investigate the resonant behaviour of an asymmetrically coupled microstrip ring resonator. Resonance splitting is theoretically predicted and experimental work carried out verifies this phenomenon. The latter is attributed to the fact that two degenerate modes are excited in this resonator. It is also shown that resonance splitting occurs only at the odd resonant frequencies when the off symmetry angle ¿ is 45°. The attractiveness of the approach presented lies in its simplicity, the resonator could find applications in microwave double-tuned narrowband filters.