Tunable dielectric compositions including low loss glass
View Patent ↗Tunable dielectric materials including an electronically tunable dielectric ceramic and a low loss glass additive are disclosed. The tunable dielectric may comprise a ferroelectric perskovite material such as barium strontium titanate. The glass additive may comprise boron, barium, calcium, lithium, manganese, silicon, zinc and/or aluminum-containing glasses having dielectric losses of less than 0.003 at 2 GHz. The materials may further include other additives such as non-tunable metal oxides and silicates. The low loss glass additive enables the materials to be sintered at relatively low temperatures while providing improved properties such as low microwave losses and high breakdown strengths.
1. A tunable dielectric material comprising:
a tunable dielectric ceramic; and
a low loss glass additive.
2. The tunable dielectric material of claim 1 , wherein the low loss glass additive comprises boron-containing glass, calcium-containing glass and/or aluminum-containing glass.
3. The tunable dielectric material of claim 1 , wherein the low loss glass additive comprises B and at least one other element selected from Si, Al, Li, Na, K, Ba, Zn, Mn and Ca.
4. The tunable dielectric material of claim 1 , wherein the low loss glass additive comprises Ca and at least one other element selected from B, Al, Si, Ba, Zn, Li, Mn and Sr.
5. The tunable dielectric material of claim 1 , wherein the low loss glass additive comprises Al and at least one other element selected from Si, B, Li, Na, K, Ba, Zn, Mn, Ca, Sr and Mg.
6. The tunable dielectric material of claim 1 , wherein the low loss glass additive comprises borosilicate glass.
7. The tunable dielectric material of claim 1 , wherein the low loss glass additive comprises lithia potash borosilicate glass.
8. The tunable dielectric material of claim 1 , wherein the low loss glass additive comprises B, Ca and Al.
9. The tunable dielectric material of claim 1 , wherein the low loss glass additive comprises from about 0.1 to about 60 weight percent of the material.
10. The tunable dielectric material of claim 1 , wherein the low loss glass additive comprises from about 0.1 to about 25 weight percent of the material.
11. The tunable dielectric material of claim 1 , wherein the low loss glass additive comprises from about 0.5 to about 15 weight percent of the material.
12. The tunable dielectric material of claim 1 , wherein the low loss glass additive comprises at least about 2 weight percent of the material.
13. The tunable dielectric material of claim 1 , wherein the low loss glass additive comprises at least about 3 weight percent of the material.
14. The tunable dielectric material of claim 1 , wherein the low loss glass additive has a dielectric loss of less than about 0.003 at a frequency of 2 GHz.
15. The tunable dielectric material of claim 1 , wherein the tunable dielectric ceramic is selected from barium strontium titanate, barium titanate, strontium titanate, barium calcium titanate, barium calcium zirconium titanate, lead titanate, lead zirconium titanate, lead lanthanum zirconium titanate, lead niobate, lead tantalate, potassium strontium niobate, sodium barium niobate/potassium phosphate, potassium niobate, lithium niobate, lithium tantalate, lanthanum tantalate, barium calcium zirconium titanate, sodium nitrate, and combinations thereof.
16. The tunable dielectric material of claim 1 , wherein the tunable dielectric ceramic comprises barium strontium titanate.
17. The tunable dielectric material of claim 1 , wherein the material further comprises a non-tunable dielectric ceramic comprising a metal oxide.
18. The tunable dielectric material of claim 1 , wherein the material further comprises a non-tunable dielectric ceramic comprising a metal silicate.
19. The tunable dielectric material of claim 1 , wherein the material further comprises at least one non-tunable dielectric ceramic comprising MgO, MgAl2O4, MgTiO3, Mg2SiO4, CaSiO3, MgSrZrTiO6, CaTiO3, Al2O3, SiO2, BaSiO3, SrSiO3, MgAl2O4, WO3, SnTiO4, ZrTiO4, CaSnO3, CaWO4, CaZrO3, MgTa2O6, MgZrO3, MnO2, PhO, Bi2O3 and/or La2O3.
20. The tunable dielectric material of claim 1 , wherein the material further comprises at least one non-tunable dielectric ceramic comprising Mg2SiO4, CaSiO3, BaSiO3, SrSiO3, MgO, CaTiO3, MgZrSrTiO6, MgTiO3, MgAl2O4, MgTa2O6 and/or MgZrO3.
21. The tunable dielectric material of claim 1 , wherein the tunable dielectric ceramic comprises barium strontium titanate and the low loss glass additive comprises B and at least one element selected from Ca, Al and Si.
22. The tunable dielectric material of claim 21 , wherein the material further comprises at least one non-tunable dielectric ceramic comprising a metal oxide or a metal silicate.
23. The tunable dielectric material of claim 22 , wherein the non-tunable dielectric ceramic comprises Mg2SiO4, CaSiO3, BaSiO3, SrSiO3, MgO, CaTiO3, MgZrSrTiO6, MgTiO3, MgAl2O4, MgTa2O6 and/or MgZrO3.
24. The tunable dielectric material of claim 1 , wherein the material has a microwave loss of less than about 0.08 at a frequency of 2 GHz.
25. The tunable dielectric material of claim 1 , wherein the material has a tunability of at least 5 percent at 4 V/micron.
26. The tunable dielectric material of claim 1 , wherein the material has a breakdown strength of at least about 80 V/micron thickness.
27. The tunable dielectric material of claim 1 , wherein the material has a sintering temperature of less than 1,200° C.
28. The tunable dielectric material of claim 1 , wherein the material has a sintering temperature of less than 1,100° C.
29. The tunable dielectric material of claim 1 , wherein the material has a sintering temperature of less than 1,000° C.
30. A tunable device comprising:
a substrate; and
a tunable dielectric material deposited on the substrate, wherein the tunable dielectric material comprises a low loss glass additive.
31. The tunable device of claim 30 , wherein the substrate comprises alumina, fosterite, zirconia or insulated metal.