Design of the Miniaturized UWB BandPass Filter Using the 1 Unit of CRLH-TL

This paper presents a new design method of the Ultra-Wide-Band BandPass Filter using the CRLH-TL(Composite Right- and Left-Handed Transmission-line) having the Metamaterials` properties. Instead of the periodic type or many cells of the CRLH-TL, only the unit cell is used to miniaturize the target component, which can not be realized by the conventional quarter guided-wavelength resonator-based filters. Particularly, the strong coupling essential to the Ultra Wide Band is enabled by the interdigital coupled lines between the grounded stubs. The proposed design scheme is validated by the electromagnetic simulation and measurement of the fabricated filter which shows the total size of `the guided-wavelength/9.4`, the 100 % fractional bandwidth for the UWB, the insertion loss of less than 1 dB and the flat group-delay.