Ring resonators are very commonly used for the design of frequency selective surfaces (FSSs). But, for some particular design, the spacing between the resonators becomes very small. So it leaves no space to shift the reflection band towards the lower side of the spectrum. It also becomes very difficult to realize large PCBs. In this paper, an improvised design of the ring resonator using stubs is reported. This provides the designer with some flexibility. Two different configurations using this concept have been fabricated. Measured results are compared with the configuration using conventional ring resonators. These results indicate good performance with tune-ability in the response without major change in the design or in the substrate.
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