Metamaterial stepped impedance resonator bandpass filter based on composite right/left-handed transmission lines

In this paper, a novel bandpass filter design using stepped impedance resonators (SIR) based on composite right/left-handed (CRLH) transmission lines is presented. In doing so, primarily CRLH SIRs are designed and characterised. They are then combined and configured to form the CRLH SIR bandpass filter. Two novel filters are successfully tested and prove to surpass their conventional counterparts. In one case, the filter can extend the spurious-free stopband to 4 × f₀. In another case, the filter size is significantly reduced by 80%.