Compact two pole bandpass filter implemented using via-free composite right/left handed transmission line with radial stubs

This paper suggests the design of a compact two-pole bandpass filter based on the via-free composite right/left-handed (CRLH) metamaterial transmission line (TL) structure with radial stubs. The Bandpass Filter (BPF) design uses these sub wavelength resonators (CRLH unit cell) along with admittance inverters to control the coupling. It is found that the suggested method enables up to 70% size reduction from the conventional filters such as the parallel coupled type which is generally designed on the basis of the half-wavelength resonance. The proposed technique is validated by experimental results.