Quasi-Elliptical Filter on Paper Substrate

The article presents the design of a bandpass filter operating in the frequency range $\mathbf{8 - 1 2} \mathbf{~ G H z}$. The filter design is designed in such a way that a filter with low insertion loss and high selectivity can be realized by using high matching SIW-resonators (Substrate Integrated Waveguide). Based on the electrodynamic analysis of its constituent elements, a bandpass SIW-filter was synthesized. To obtain high selectivity and low insertion loss, a quasi-elliptic filter using positive and negative coupling is used. Negative connections are assessed by the holes between the resonators and the gaps in the ground planes. Dimensions of the proposed filter: $7.6 \mathrm{~mm} \times 4.6 \mathrm{~mm}$. The substrate material is thick paper, the dielectric thickness is 0.15 mm with the dielectric constant of the substrate $\varepsilon=2.85$, metallization thickness is 35 microns. The paper shows the process of modeling and synthesis of a bandpass filter that was manufactured, as well as a comparison of their amplitude-frequency characteristics, which showed a good match.