LTCC based substrate integrated waveguide (SIW) bandpass filters with CPW transitions

In this work, substrate integrated waveguide (SIW) bandpass filters were designed and fabricated using LTCC process. The proposed scheme consists of SIW cavities with coupling slots and coplanar waveguide (CPW) transitions. To reduce the component size and surface occupation, three SIW cavities are laminated vertically. Both horizontal transition and vertical transition are used between the two CPW transmission lines. Based on the SICCAS-K70D LTCC material (εr = 66, tanδ = 0.002 @3.5 GHz), an S-band bandpass filter with a center frequency of 2.59 GHz was designed and fabricated using the in-house developed LTCC material and process.