Fig. 1. Schematic diagram of an asymmetric rectangular ring resonator MIM filter

Fig. 2. Transmission spectrum diagram. (a) Transmission spectra of three different structures of rectangular ring cavity; (b) transmission spectrum of structure 3

Fig. 3. Transmission spectra of the three different rectangular ring cavity structure filters

Fig. 4. Magnetic field distribution of the ring cavity structure. (a)--(c) Single rectangular ring cavity structure with λ=916, 1140, 2012 nm; (d)--(f) symmetric rectangular ring cavity structure with λ=912, 1136, 2012 nm; (g)--(i) asymmetrical rectangular ring cavity structure with λ=908, 1136, 1996 nm

Fig. 5. Effect of changing the structure parameter h on the transmission characteristics of rectangular ring cavity filter. (a) Transmission spectrum; (b) resonance wavelength

Fig. 6. Effect of changing the structure parameter L on the transmission characteristics of rectangular ring cavity filter. (a) Transmission spectrum; (b) resonance wavelength

Fig. 7. Effect of changing the structure parameter d on the transmission characteristics of rectangular ring cavity filter. (a) Transmission spectrum; (b) resonance wavelength

Fig. 8. Effect of changing the applied voltage U on the transmission characteristics of rectangular ring cavity filter. (a) Transmission spectrum; (b) resonance wavelength

Fig. 9. Multiple rectangular ring cavities structure. (a) Schematic diagram; (b) transmission spectrum

Fig. 10. Transmission spectra at different voltages