Coupled transmission line resonate RF filter
The present invention includes a method of creating electrical air gap low loss low cost RF mechanically and thermally stabilized interdigitated resonate filter in photo definable glass ceramic substrate. Where a ground plane may be used to adjacent to or below the RF filter in order to prevent parasitic electronic signals, RF signals, differential voltage build up and floating grounds from disrupting and degrading the performance of isolated electronic devices by the fabrication of electrical isolation and ground plane structures on a photo-definable glass substrate.
1. A method of making a mechanically stabilized RF coupled interdigitated resonant device comprising:
providing a photosensitive glass substrate;
masking a design layout comprising one or more interdigitated structures to form one or more interdigitated resonators on the photosensitive glass substrate, wherein each interdigitated resonator is rectangular, and wherein adjacent interdigitated resonators are configured and disposed to couple a signal of a frequency of about 26 to 30 GHz;
exposing at least one portion of the photosensitive glass substrate to an activating energy source;
heating the photosensitive glass substrate for at least ten minutes above a glass transition temperature thereof;
cooling the photosensitive glass substrate to transform at least part of the exposed glass to a crystalline material to form a glass-crystalline substrate;
etching the glass-crystalline substrate with an etchant solution to form a glass mechanical support structure from the photosensitive glass substrate; and
coating the one or more interdigitated structures, a ground plane, an input channel, and an output channel with one or more metals, wherein the one or more metals are configured to be connected to a circuitry.
2. The method of claim 1 , further comprising covering all or part of an external electrical isolation structure of the device with a metal or metallic media lid; and grounding the metal or metallic media lid.
3. The method of claim 1 , wherein the mechanical support structure has a contact area with the one or more interdigitated structures that is less than 50%, 40%, 35%, 30%, 25%, 20%, 10%, 5% or 1% of a contact area of the one or more interdigitated structures.
4. The method of claim 1 , wherein the coating the one or more interdigitated structures forms the one or more interdigitated resonators.
5. The method of claim 1 , wherein the one or more interdigitated resonators form a bandpass filter, a low-pass filter, a high-pass filter, or a notch filter.
6. The method of claim 5 , wherein the one or more interdigitated resonators comprise titanium, titanium-tungsten, chrome, copper, nickel, gold, palladium, or silver.
7. The method of claim 1 , wherein the step of etching forms an air gap between the photosensitive glass substrate and the one or more interdigitated structures.
8. The method of claim 1 , further comprising converting the glass-crystalline substrate adjacent to the one or more interdigitated structures to a ceramic phase.
9. The method of claim 1 , wherein the one or more metals are selected from iron, copper, gold, nickel, indium, silver, platinum, or palladium.
10. The method of claim 1 , wherein the one or more metals are configured to be connected to the circuitry through a surface a buried contact, a blind via, a glass via, a straight line contact, a rectangular contact, a polygonal contact, or a circular contact.
11. The method of claim 1 , wherein the photosensitive glass substrate comprises a composition of: 60 to 76 weight % silica; at least 3 weight % K 2 O with 6 to 16 weight weight % of a combination of K 2 O and Na 2 O; 0.003 to 1 weight % of at least one oxide selected from the group consisting of Ag 2 O and Au 2 O; 0.003 to 2 weight % Cu 2 O; 0.75 to 7 weight % B 2 O 2 , and 6 to 7 weight % Al 2 O 3 , with the combination of B 2 O 3 ; and Al 2 O 3 not exceeding 13 weight %; 8 to 15 weight % Li 2 O; and 0.001 to 0.1 weight % CeO 2 .
12. The method of claim 1 , wherein the photosensitive glass substrate comprises a composition of: 35 to 76 weight % silica, 3 to 16 weight % K 2 O, 0.003 to 1 weight % Ag 2 O, 8 to 15 weight % Li 2 O, and 0.001 to 0.1 weight % CeO 2 .
13. The method of claim 1 , wherein the photosensitive glass substrate comprises at least one of: at least 0.1 weight % Sb 2 O 3 or As 2 O 3 ; 0.003 to 1 weight % Au 2 O; 1 to 18 weight % of an oxide selected from the group consisting of CaO, ZnO, PbO, MgO, SrO, and BaO; and an anisotropic-etch ratio of an exposed portion to an unexposed portion at least one of 10 to 20:1; 21 to 29:1; 30 to 45:1; 20 to 40:1; 41 to 45:1; and 30 to 50:1.
14. The method of claim 1 , wherein the photosensitive glass substrate is a photosensitive glass ceramic composite substrate comprising at least one of silica, lithium oxide, aluminum oxide, or cerium oxide.
15. The method of claim 1 , wherein an RF transmission through the mechanically stabilized RF coupled interdigitated resonant device has a loss of less than 50, 40, 30, 25, 20, 15, or 10% of a signal input versus a signal output.
16. The method of claim 1 , the one or more interdigitated resonators form a feature of a bandpass filter, a low-pass filter, a high-pass filter, or a notch filter.
17. A mechanically stabilized RF coupled interdigitated resonant device made by a method comprising:
providing a photosensitive glass substrate;
masking a design layout comprising one or more structures to form one or more interdigitated resonators on the photosensitive glass substrate, wherein each interdigitated resonator is rectangular, and wherein adjacent interdigitated resonators are configured and disposed to couple a signal of a frequency of about 26 to 30 GHz;
exposing at least one portion of the photosensitive glass substrate to an activating energy source;
heating the photosensitive glass substrate for at least ten minutes above glass transition temperature thereof;
cooling the photosensitive glass substrate to transform at least part of the exposed glass to a crystalline material to form a glass-crystalline substrate;
etching the glass-crystalline substrate with an etchant solution to form a glass mechanical support structure from the photosensitive glass substrate;
coating the one or more interdigitated structures, a ground plane, an input channel, and an output channel with one or more metals; and
connecting the mechanically stabilized RF coupled interdigitated resonant device to a circuitry.
18. The device of claim 17 , wherein the method for making the device further comprises covering all or part of an external electrical isolation structure of the device with a metal or metallic media lid; and grounding the metal or metallic media lid.
19. The device of claim 17 , wherein the mechanical support structure has a contact area with the one or more interdigitated structures that is less than 50%, 40%, 35%, 30%, 25%, 20%, 10%, 5% or 1% of the contact area of the one or more interdigitated structures.
20. The device of claim 17 , wherein the coating the one or more interdigitated structures forms the one or more interdigitated resonators.
21. The device of claim 17 , wherein the one or more interdigitated resonators form a bandpass filter, a high-pass filter, a low-pass filter, or a notch filter.
22. The device of claim 21 , wherein the one or more interdigitated resonators comprise titanium, titanium-tungsten, chrome, copper, nickel, gold, palladium, or silver.
23. The device of claim 17 , wherein the step of etching forms an air gap between the photosensitive glass substrate and the one or more interdigitated structures.
24. The device of claim 17 , wherein the method further comprises converting the glass-crystalline substrate adjacent to the one or more interdigitated structures to a ceramic phase.
25. The device of claim 17 wherein the one or more metals are selected from iron, copper, gold, nickel, indium, silver, platinum, or palladium.