Compact triple-band resonators using multiple split-ring resonators

A new design for a triple-mode resonator based on multiple split-ring resonators is introduced. All three modes exhibit very high unloaded Q-factors ranging from 100 to 240 which is suitable for design of high selectivity filters. This structure exhibits transmission zeros between passbands. Changing the ring dimensions allows the resonant frequencies and bandwidths of the modes to be controlled. The effects of substrate thickness, ring widths and spacing and total resonator size are investigated and described. Measured data for two different resonators are compared to simulated data and very good agreement was found.