Electric coupling of a substrate integrated waveguide cavity resonator to a suspended substrate stripline low pass filter for introducing a notch response

A Suspended Substrate Stripline (SSS) Low Pass Filter (LPF) comprising:

• a substrate having metal layers formed on a top surface and a bottom surface thereof;
• a LPF circuit formed on a non-metalized area of the top surface of the substrate and positioned between a pair of the metal layers formed on the top surface of the substrate;
• a top ground plate having a first air cavity formed on a bottom surface of the top ground plate, wherein the first air cavity on the top ground plate is positioned directly above the LPF circuit when the top ground plate is positioned on the top surface of the substrate;
• a bottom ground plate having a second air cavity formed on a top surface of the bottom ground plate, wherein the second air cavity on the bottom ground plate is positioned directly below the LPF circuit when the bottom ground plate is positioned on the bottom surface of the substrate;
• a Substrate Integrated Waveguide (SIW) cavity resonator coupled to the LPF circuit to create a notch response in the SSS LPF;
• and
• a plurality of vias, wherein the plurality of vias comprises:
• two parallel rows of vias extending through the substrate, wherein the filter is positioned between the parallel rows of vias;
• and
• a set of vias extending through the substrate delimiting an area of the SIW cavity resonator;
• and
• an opening is formed in the set of vias delimiting the area of the SIW cavity resonator for coupling the SIW cavity resonator to the LPF circuit.

A Suspended Substrate Stripline (SSS) Low Pass Filter (LPF) comprising:

• a substrate having metal layers formed on a top surface and a bottom surface thereof;
• a LPF circuit formed on a non-metalized area of the top surface of the substrate and positioned between a pair of the metal layers formed on the top surface of the substrate;
• a top ground plate having a first air cavity formed on a bottom surface of the top ground plate, wherein the first air cavity on the top ground plate is positioned directly above the LPF circuit when the top ground plate is positioned on the top surface of the substrate;
• a bottom ground plate having a second air cavity formed on a top surface of the bottom ground plate, wherein the second air cavity on the bottom ground plate is positioned directly below the LPF circuit when the bottom ground plate is positioned on the bottom surface of the substrate;
• a pair of Substrate Integrated Waveguide (SIW) cavity resonators coupled to the LPF circuit to create a notch response in the SSS LPF;
• and
• a plurality of vias, wherein the plurality of vias comprises:
• two parallel rows of vias extending through the substrate, wherein the filter is positioned between the parallel rows of vias;
• a first set of vias extending through the substrate delimiting an area of a first SIW cavity resonator, wherein an opening is formed in the first set of vias delimiting the area of the first SIW cavity resonator for coupling the first SIW cavity resonator to the LPF circuit;
• and
• a second set of vias extending through the substrate delimiting an area of a second SIW cavity resonator, wherein an opening is formed in the second set of vias delimiting the area of the second SIW cavity resonator for coupling the second SIW cavity resonator to the LPF circuit.