Dual-Band Bandpass and Bandstop Filters Using Composite Right/Left-Handed Metamaterial Transmission Lines

In this paper, dual-band bandpass and bandstop filters using composite right/left-handed (CRLH) metamaterial transmission lines (TLs) are developed. The conventional bandpass and bandstop filters are first designed using quarter-wave short-circuited and open-circuited stubs, respectively. Then the dual-band filters with arbitrary dual operating bands can then be easily implemented by replacing the microstrip lines with the CRLH TLs. The dual-band bandpass and bandstop filters using the CRLH TLs are experimentally demonstrated at dual operating frequencies 1 GHz and 1.9 GHz. The measured results are in a good agreement with the simulated results. From the measured performances, the dual-band bandpass filter has 29.8% and 17.3% pass bandwidths, while the dual-band bandstop filter has 12.2% and 6.9% stop bandwidths with 30dB attenuation