A novel dual band filter has been proposed. It is shown that the two transmission bands can be excited and designed using proposed resonators which combine an open-loop resonator and the composite right/left-handed (CRLH) material structure. The CRLH material structure is embedded into the ends of the folded open-loop resonators. The open-loop resonator can excite the low-band resonant frequency and the circuit which is designed to be unbalanced, a left handed (LH) mode in the β-ω diagram can control the high-band resonant frequency. With dual-feeding structures added, the performances of the filter such as frequency selectivity and insertion loss are much improved. Besides, the embedded resonators structure (EMRs) can further miniaturize the dimensions of the overall structure. Finally, a novel dual band filter based on the 0° feeding structure has been designed and fabricated with 2.4 and 1.1 dB insertion loss at the center frequency of 2.45 and 5.2 GHz. Experimental circuits on substrates with εr =3.38 are measured to validate the theory and design. The die size of the scheme is 10 mm × 8.55 mm.