Multi-layer digital elliptic filter and method
View Patent ↗The present invention relates generally to digital elliptic filters, and more particularly, but not exclusively to multi-layer digital elliptic filters and methods for their fabrication.
1. A digital elliptic filter, comprising:
a plurality of conductive walls defining an enclosure disposed therein;
a first conductive post disposed within the enclosure and having an end thereof electrically connected to a selected one of the plurality conductive walls, the post having a longitudinally extending stub cavity disposed therein; and
a second conductive post disposed within the enclosure with an end thereof electrically connected to the selected conductive wall, the second conductive post having a conductive stub extending along a longitudinal axis of the second conductive post and disposed within the stub cavity,
wherein the first and second conductive posts, conductive stub, and the plurality of conductive walls each comprise a plurality of layers of a conductive material, and are configured to have inductive and capacitive properties to provide a digital elliptic filter.
2. The digital elliptic filter according to claim 1 , wherein the conductive stub is partially contained within the stub cavity.
3. The digital elliptic filter according to claim 1 , wherein the conductive stub is fully contained within the stub cavity.
4. The digital elliptic filter according to claim 1 , wherein the conductive stub is L-shaped.
5. The digital elliptic filter according to claim 1 , wherein first conductive post has a C-shaped cross-section taken perpendicular to the longitudinal axis thereof.
6. The digital elliptic filter according to claim 1 , wherein the stub cavity comprises a longitudinal wall extending along a longitudinal axis of the first post, the longitudinal wall having a notch disposed therein.
7. The digital elliptic filter according to claim 6 , wherein a portion of the stub is disposed within the notch to provide the electrical connection between the stub and the first conductive post.
8. The digital elliptic filter according to claim 1 , comprising a low pass filter disposed in series therewith.
9. The digital elliptic filter according to claim 1 , comprising a third conductive post disposed within the enclosure, the third conductive post having a stub cavity disposed therein, and wherein the first conductive post has a conductive stub extending along a longitudinal axis thereof and the conductive stub of the first conductive post is disposed within the stub cavity of the third conductive post.
10. A method of forming a digital elliptic filter by a sequential build process, comprising:
depositing a plurality of layers, wherein the layers comprise one or more of a conductive material and a sacrificial photoresist material, thereby forming a structure comprising:
a plurality of conductive walls defining an enclosure disposed therein;
a first conductive post disposed within the enclosure and having an end thereof electrically connected to a selected one of the plurality conductive walls, the post having a longitudinally extending stub cavity disposed therein; and
a second conductive post disposed within the enclosure with an end thereof electrically connected to the selected conductive wall, the second conductive post having a conductive stub extending along a longitudinal axis of the second conductive post and disposed within the stub cavity,
wherein the first and second conductive posts, conductive stub, and the plurality of conductive walls each comprise a plurality of layers of a conductive material, and are configured to have inductive and capacitive properties to provide a digital elliptic filter; and
removing the sacrificial photoresist.
11. The method of forming a digital elliptic filter by a sequential build process according to claim 10 , wherein the conductive stub is partially contained within the stub cavity.
12. The method of forming a digital elliptic filter by a sequential build process according to claim 10 , wherein the conductive stub is fully contained within the stub cavity.
13. The method of forming a digital elliptic filter by a sequential build process according to claim 10 , wherein the conductive stub is L-shaped.
14. The method of forming a digital elliptic filter by a sequential build process according to claim 10 , wherein first conductive post has a C-shaped cross-section taken perpendicular to the longitudinal axis thereof.
15. The method of forming a digital elliptic filter by a sequential build process according to claim 10 , wherein the stub cavity comprises a longitudinal wall extending along a longitudinal axis of the first post, the longitudinal wall having a notch disposed therein.
16. The method of forming a digital elliptic filter by a sequential build process according to claim 15 , wherein a portion of the stub is disposed within the notch to provide the electrical connection between the stub and the first conductive post.
17. The method of forming a digital elliptic filter by a sequential build process according to claim 10 , wherein the structure comprises a third conductive post disposed within the enclosure, the third conductive post having a stub cavity disposed therein, and wherein the first conductive post has a conductive stub extending along a longitudinal axis thereof and the conductive stub of the first conductive post is disposed within the stub cavity of the third conductive post.