Design of a SIW Chebyshev Bandpass Filter with Inductive Coupling

In this paper, is presented a Chebyshev bandpass filter using the substrate integrated waveguide (SIW) technology, a coplanar waveguide (CPW) on the input and output ports and a shunt inductance to perform the coupling between the resonant cavities. The CPW-SIW transitions used the 50 Ω step impedance between the input/output feeding line and the transition to control the filter's input/output couplings. Besides that, the proposed filter is low-cost, since it is manufactured using a printed circuit board (PCB). The presented SIW filter was validated by simulation and measurements, since coherent results were obtained in both methods. A return loss of -50 dB and a minimum insertion loss of -3.3 dB in the bandpass were accomplished, with a bandwidth of 60 MHz at the center frequency of 2.26 GHz.