Dual-band bandpass filter using composite metamaterial resonator

A dual-band bandpass filter at X-band is proposed using composite rnetarnaterial resonator consisting of an outer square closed-ring resonator (SCRR) and two inner electric inductance capacitance (ELC) resonators. Numerical simulation and microwave measurement reveal that the filter exhibits two passbands centered at 8.76 GHz and 1-1.04 G Hz, with 3 dB bandwidths of-130 MHz and 290 MHz, respectively. The complex dispersion relation of the filter is further derived based on the effective medium theory, where two balanced composite right-/left-handed bands are found, i.e. lines exhibiting two left-handed and two right-handed bands alternating. The proposed filter may find useful in dual-banal or multi-band wireless communication Systems.