Wideband band-pass filters with spurious band suppression

In this paper, we investigate the cause of the second harmonic of the parasitic pass-band of coupled-serial-shunted lines band-pass filters. Filters are employed substrate suspension, wavy-edge coupling, ring resonators, and a combination of the wavy-edge coupling and ring resonators to suppress the harmonic pass-band. Using a continuous perturbation of the wavy-edge and ring resonators of the harmonic pass-band of the parallel-coupled line filter is rejected. A synthesizing method is presented to design Chebyshev type II band-pass filters in the microwave frequency range. Chebyshev type II band-pass filters are implemented to validate this method correct by measuring.