Electronically tunable, low-loss ceramic materials including a tunable dielectric phase and multiple metal oxide phases

• US 20040089985A1
• Filed: 10/16/2003
• Published: 05/13/2004
• Est. Priority Date: 01/24/2001
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Blackberry Limited
• Inventors: Sengupta, Louise C., Zhang, Xubai, Chiu, Luna H.
• Granted Patent: US 8,562,899 B2
• Time in Patent Office: Days
• US Class Current: 264/614
• CPC Class Codes: C04B 35/462 based on titanates
• CPC Class Codes: C04B 35/495 based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates

Abstract

Electronically tunable dielectric materials having favorable properties are disclosed. The electronically tunable materials include an electronically tunable dielectric phase such as barium strontium titanate in combination with at least two additional metal oxide phases. The additional metal oxide phases may include, for example, oxides of Mg, Si, Ca, Zr, Ti and Al. The electronically tunable materials may be provided in bulk, thin film and thick film forms for use in devices such as phased array antennas, tunable filters and the like. The materials are useful in many applications, including the area of radio frequency engineering and design.

Claims

1. A method of making an electronically tunable dielectric material comprising:

mixing particles of at least one electronically tunable dielectric material and a total of from about 1 to about 80 weight percent of particles of at least two additional metal oxide materials; and

sintering the material.

2. The method of claim 1, wherein the electronically tunable dielectric particles and the additional metal oxide particles have average particle sizes of from about 0.1 to about 5 micron.

3. The method of claim 1, wherein the electronically tunable dielectric particles and the additional metal oxide particles have average particle sizes of from about 1.5 to about 2.5 micron.

4. The method of claim 1, wherein the additional metal oxide phases comprise a total of from about 3 to about 65 weight percent of the material.

5. The method of claim 1, wherein the additional metal oxide phases comprise a total of from about 5 to about 60 weight percent of the material.

6. The method of claim 1, wherein the additional metal oxide phases comprise a total of from about 10 to about 50 weight percent of the material.

7. The method of claim 1, wherein the dielectric material consists essentially of two of the additional metal oxide phases.

8. The method of claim 7, wherein the two additional metal oxide phases have a weight ratio of from about 1:

100 to about 100;

1.

9. The method of claim 7, wherein the two additional metal oxide phases have a weight ratio of from about 1:

10 to about 10;

1.

10. The method of claim 7, wherein the two additional metal oxide phases have a weight ratio of from about 1:

5 to about 5;

1.

11. The method of claim 1, wherein the at least one electronically tunable dielectric phase 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.

12. The method of claim 1, wherein the at least one electronically tunable dielectric phase comprises barium strontium titanate.

13. The method of claim 12, wherein the barium strontium titanate is of the formula Ba_xSr_1-xTiO₃, where x is from about 0.15 to about 0.6.

14. The method of claim 1, wherein the additional metal oxide phases comprise oxides of at least two metals selected from Be, Mg, Ca, Sr, Ba, Ra, Li, Na, K, Rb, Cs, Al, Zr, Zn, Fr, B, Fe, Mn, Cu, Cr, Ti, Ta, Nb, Mo, W, Ni, Pd, Pb, Bi, Si, Sn, Hf and rare earths.

15. The method of claim 1, wherein the additional metal oxide phases comprise oxides of at least two metals selected from Mg, Si, Ca, Zr, Ti and Al.

16. The method of claim 1, wherein the additional metal oxide phases comprise at least two Mg-containing compounds.

17. The method of claim 16, further comprising at least one Mg-free compound.

18. The method of claim 17, wherein the Mg-free compound comprises an oxide of a metal selected from Si, Ca, Zr, Ti and Al.

19. The method of claim 17, wherein the Mg-free compound comprises a rare earth oxide.

20. The method of claim 1, wherein the additional metal oxide phases comprise a Mg-containing compound and a Mg-free compound.

21. The method of claim 20, wherein the Mg-free compound comprises an oxide of a metal selected from Si, Ca, Zr, Ti and Al.

22. The method of claim 1, wherein the additional metal oxide phases comprise at least one material selected from Mg₂SiO₄, MgO, CaTiO₃, MgZrSrTiO₆, MgTiO₃, MgAl₂O₄, WO₃, SnTiO₄, ZrTiO₄, CaSiO₃, CaSnO₃, CaWO₄, CaZrO₃, MgTa₂O₆, MgZrO₃, MnO₂, PbO, Bi₂O₃ and La₂O₃.

23. The method of claim 1, wherein the additional metal oxide phases comprise at least one material selected Mg₂SiO₄, MgO, CaTiO₃, MgZrSrTiO₆, MgTiO₃, MgAl₂O₄, MgTa₂O₆ and MgZrO₃.

24. The method of claim 1, wherein the material has a tunability of at least 25 percent at 8V/micron.

25. The method of claim 1, wherein the material has a tunability of at least 30 percent at 8V/micron.