Systems, methods, and apparatus for electrical filters and input/output systems
View Patent ↗An electronic filtering device includes continuous trace on a dielectric substrate and a dissipation layer communicatively coupled to the trace. The dissipation layer may include disconnected metal particles, which may be embedded in a substrate, for example in an epoxy. The continuous trace may be meandering, for example crenulated, coil or spiral signal path. At least a second continuous trace may be spaced from the first by the substrate, and conductively coupled by a via. The electronic filtering device may be used in one or more printed circuit boards (PCBs) that form stages of an input/output system.
1. An electrical signal filtering device comprising:
a dielectric medium;
a first continuous conductive path carried by the dielectric medium that forms a first circuitous route for connecting a first pair of points on the dielectric medium, the first continuous conductive path comprising a first conductive layer formed of a conductive metal having a first resistance and a first dissipative layer formed of a conductive metal having a second resistance that is higher than the first resistance, the first conductive layer and the first dissipative layer plated one on top of the other such that the first conductive layer provides a path through which an electrical signal flows and the first dissipative layer provides dissipation of unwanted signal frequencies; and
a second continuous conductive path that establishes a second circuitous route for connecting a second pair of points, the second continuous conductive path spaced from the first continuous conductive path by at least a portion of the dielectric medium, wherein the first continuous conductive path is galvanically coupled to the second continuous conductive path by a via connection extending through at least a portion of the dielectric medium.
2. The filtering device of claim 1 wherein at least a portion of the conductive metal in the first dissipative layer is coupled to ground.
3. The filtering device of claim 1 , further comprising a plurality of disconnected metal particles embedded in at least a portion of the dielectric medium.
4. The filtering device of claim 1 , further comprising a plurality of disconnected metal particles embedded in at least a portion of an epoxy substance, wherein at least a portion of the epoxy substance is in contact with at least a portion of the dielectric medium.
5. The filtering device of claim 1 wherein the first circuitous route is a meandering signal path that connects the first pair of points on the dielectric medium by a plurality of changes in direction across a width of the dielectric medium, and wherein the first pair of points includes a first point near a first end of the dielectric medium and a second point near an opposite end of the dielectric medium along a length of the dielectric medium.
6. The filtering device of claim 1 wherein the first circuitous route is at least one of a coil signal path and a spiral signal path that connects the first pair of points on the dielectric medium by concentric turns inwards from a perimeter of the dielectric medium towards a center of the dielectric medium, and wherein the first pair of points includes a first point near the perimeter of the dielectric medium and a second point near the center of the dielectric medium.
7. The filtering device of claim 1 wherein the second continuous conductive path comprises a second conductive layer formed of a first conductive metal and a second dissipative layer formed of a second conductive metal, and wherein a resistance of the second conductive metal is higher than a resistance of the first conductive metal and the second conductive layer and the second dissipative layer are plated one on top of the other such that the second conductive layer provides a path through which an electrical signal flows and the second dissipative layer provides dissipation of unwanted signal frequencies.
8. The filtering device of claim 1 wherein the second circuitous route is a meandering signal path that connects the second pair of points by a plurality of changes in direction across a width of the dielectric medium, and wherein the second pair of points includes a first point near a first end of the dielectric medium and a second point near an opposite end of the dielectric medium along a length of the dielectric medium.
9. The filtering device of claim 1 wherein the second circuitous route is at least one of a coil signal path and a spiral signal path that connects the second pair of points by concentric turns inwards from a perimeter of the dielectric medium towards a center of the dielectric medium, and wherein the second pair of points includes a first point near the perimeter of the dielectric medium and a second point near the center of the dielectric medium.
10. The electrical signal filtering device of claim 1 , further comprising:
a first shielding layer comprising an approximately uniform metal plane; and
a second shielding layer comprising an approximately uniform metal plane, wherein both the first continuous conductive path and the second continuous conductive path are situated in between the first and the second shielding layers, and wherein a number of edges of the dielectric medium are plated with shielding metal such that both the first continuous conductive path and the second continuous conductive path are at least partially enclosed by the shielding metal of the first and the second shielding layers and the plated edges.
11. The filtering device of claim 1 wherein the dielectric medium, the first continuous conductive path, and the second continuous conductive path form a printed circuit board.
12. The filtering device of claim 11 wherein the printed circuit board includes a flexible printed circuit board.
13. The filtering device of claim 1 wherein the conductive metal in the first conductive layer is formed of a material that is superconducting below a critical temperature such that the first resistance is substantially zero and the conductive metal in the first dissipative layer is formed of a material that is not superconducting below the critical temperature such that the second resistance is not zero.
14. The filtering device of claim 1 wherein the dielectric medium comprises a first surface and a second surface, and wherein the first continuous conductive path is carried on the first surface and the second continuous conductive path is carried on the second surface.
15. The filtering device of claim 1 wherein the dielectric medium comprises multiple layers, and wherein the first continuous conductive path is carried on a first layer and the second continuous conductive path is carried on a second layer.
16. The filtering device of claim 1 wherein the conductive metal in the first conductive layer is carried directly on the dielectric medium and the conductive metal in the first dissipative layer is plated upon the conductive metal in the first conductive layer.
17. The filtering device of claim 1 wherein the conductive metal in the first dissipative layer is carried directly on the dielectric medium and the conductive metal in the first conductive layer is plated on the conductive metal in the first dissipative layer.