Fig. 1. Dispersion curves of gradual slot unit structure

Fig. 2. Dispersion curves of gradual slot unit structure at different h

Fig. 3. Structure of filter. (a) Low-pass filter; (b) transition section; (c) coplanar waveguide section

Fig. 4. Simulated S-parameter curves of low-pass filter

Fig. 5. Structure of multiband filter

Fig. 6. Model of the equivalent circuit. (a) E-shaped resonator; (b) odd mode; (c) even mode

Fig. 7. Deformation model of even mode equivalent circuit

Fig. 8. Influence of L_a and L_b change on S₂₁. (a) L_a; (b) L_b

Fig. 9. S-parameter curves of three-band filter

Fig. 10. S-parameter curves of dual-band filter