Herein, a metal-insulator-metal asymmetric circular structure comprising two circular cavities, a transmission waveguide, and two coupled waveguides is proposed. The coupling effect of surface plasmon polaritons is strengthened through the local effect of resonant cavities, and a good extraordinary transmission is obtained. The effects of the radii and number of circular resonant cavities and that of the inter-circle distance on such an extraordinary transmission are investigated via the finite difference time domain method. The results show that in the case that the radius of the circular resonant cavity resonator and the inter-circle distance are 100 nm and 200 nm, respectively, the structure exhibits a very good extraordinary transmission. The optimization of these main parameters could allow an average stopband width of 1000 nm and increase the working range up to 2500 nm.