Triangular resonators re-shaped with the Sierpinski geometry have been designed, implementing them with single-pole-double-through (SPDT) RF MEMS switches to provide fine-tuning for potential applications in the K-Band. Prototypes of band-stop filters working at 20 GHz and 26 GHz, for RADAR and satellite communications have been studied in coplanar waveguide (CPW) configuration. The tuning was obtained by switching between two device branches loaded with different resonators. As a result, dual-band operation can be obtained depending on the choice of the resonator. The studied filters belong to the more general group of devices inspired by the metamaterial design.