Novel Dual-composite Right/left-handed Transmission Line and Its Application to Bandstop Filter

A novel structure of dual-composite right/left-handed transmission line (D-CRLH-TL) is proposed in this paper, and its electromagnetic characteristics are investigated in theory and simulation. The dispersion curve of the proposed structure has been derived by using Bloch-Floquet theory. The structure is composed with an “H”-shaped defected ground structure (DGS) and two stubs with rectangular patches, compared with the structure of D-CRLHTL proposed in paper [6, 7], this structure is simpler and more easily adjusted. Then, an ultra wide-stopband (UWSB) bandstop filter based on the proposed D-CRLH-TL is designed, fabricated, and measured. The simulated and measured results show that the centre frequency of the filter is 5.1 GHz, the bandwidth of stopband is 90.2%, and the filter has sharp transmissions at the two edges of the stop-band. Besides, the designed filter in this paper has a smaller size than traditional ones, and can be easily fabricated.