Engineering of metamaterials based cut-band to bandpass filters

Metamaterial based filters are often made by placing Split Ring Resonator (SRR) along a microstrip line or by using their complementary structure (Complementary SRR -CSRR) under it. Due to the behavior of resonators, the obtained rejection gets a high quality factor. The width of this rejection can however be increased by gradually varying the size of the SRR resonators along the line and then that could create a cut-band filter. In addition, by combining two arrays of resonators of progressively increasing size, a bandpass filter can then be obtained.