Generalized Chebyshev SIW Filter Based on a Novel Negative-slope Dispersive Coupling Structure

A novel dispersive coupling structure with realization of negative slope is proposed based on substrate integrated waveguide (SIW). The dispersive coupling is constructed by two coupled shorted-end grounded coplanar waveguides (SEGCPWs) cooperated with the inductive coupling window. The characteristics of the discontinuity are studied, which indicates that the proposed dispersive coupling has advantages of flexibly controllable negative slope and position of zero. And it may be employed for generalized Chebyshev filters with dispersive couplings. For the verification, a 4th-order SIW bandpass filter (BPF) in quadruplet, using the proposed dispersive coupling structure, was designed, fabricated and measured. Measured results agree well with simulated ones.