Temperature compensated dielectric material

• US 10,315,959 B2
• Filed: 09/25/2017
• Issued: 06/11/2019
• Est. Priority Date: 09/29/2016
• Status: Active Grant

• Current Assignee: Skyworks Solutions Incorporated
• Original Assignee: Skyworks Solutions Incorporated
• Inventors: Hill, Michael David
• Primary Examiner(s): Group, Karl E
• Application Number:
  US15/714,934
• Publication Number:
  US 20180086673A1
• Time in Patent Office: 624 Days
• CPC Class Codes: C01B 13/145 After-treatment of oxides or hydroxides, e.g. pulverising, drying, decreasing the acidity
• CPC Class Codes: C01G 23/003 Titanates C01G23/001 takes precedence
• CPC Class Codes: C01G 33/006 Compounds containing, besides niobium, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01P 2002/76 by a space-group or by other symmetry indications
• CPC Class Codes: C01P 2006/10 Solid density
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3251 Niobium oxides, niobates, tantalum oxides, tantalates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/72 Products characterised by the absence or the low content of specific components, e.g. alkali metal free alumina ceramics
• CPC Class Codes: C04B 2235/76 Crystal structural characteristics, e.g. symmetry
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 35/462 based on titanates
• CPC Class Codes: C04B 35/4686 based on phases other than BaTiO3 perovskite phase
• CPC Class Codes: C04B 35/499 containing also titanates
• CPC Class Codes: C04B 35/6262 of calcined, sintered clinker or ceramics
• CPC Class Codes: C04B 35/62675 characterised by the treatment temperature
• CPC Class Codes: H01B 3/12 ceramics

Abstract

Disclosed are embodiments of tungsten bronze crystal structures that can have both a high dielectric constant and low temperature coefficient, making them advantageous for applications that experience temperature changes and gradients. In particular, tantalum can be substituted into the crystal structure to improve properties. Embodiments of the material can be useful for radiofrequency applications such as resonators and antennas.

Claims

1. A ceramic material comprising:

Ba, Sm, Ti, Ta, and O having a tungsten bronze crystal structure, the ceramic material having a dielectric constant of at least 60, and temperature coefficient of resonant frequency of less than 15, and a Qf at 1 GHz of at least 7000.

2. The ceramic material of claim 1 wherein the ceramic material contains no aluminum.

3. The ceramic material of claim 1 wherein the ceramic material has a dielectric consent of at least 80.

4. The ceramic material of claim 1 wherein the temperature coefficient of resonant frequency of the ceramic material is less than 5.

5. The ceramic material of claim 1 wherein the ceramic material has a Qf at 1 GHz of at least 8000.

13. The ceramic material of claim 1 wherein the ceramic material has no rutile or perovskite phase.

14. The ceramic material of claim 1 wherein the ceramic material has a Qf at 1 GHz of at least 7000.

6. A ceramic material having a high dielectric constant while maintaining a low temperature coefficient of resonant frequency, the ceramic material comprising:

a chemical formula Ba_12+3xSm<sub>28−

3x</sub>Ti<sub>54−

3x</sub>Ta_3xO₁₆₂, x being between 0 and having

a tungsten bronze crystal structure.

7. The ceramic material of claim 6 wherein the ceramic material has a chemical formula of Ba_12.6Sm_27.4Ti_53.4Ta_0.6O₁₆₂.

8. The ceramic material of claim 6 wherein the ceramic material has a dielectric constant of at least 60 and a temperature coefficient of resonant frequency of less than 15.

9. The ceramic material of claim 8 wherein the temperature coefficient of resonant frequency is less than 5.

10. The ceramic material of claim 6 wherein the ceramic material has no rutile or perovskite phase.

11. The ceramic material of claim 6 wherein the ceramic material has a Qf at 1 GHz of at least 7000.

12. The ceramic material of claim 6 wherein the ceramic material has a Qf at 1 GHz of at least 8000.

15. A ceramic material having a high dielectric constant while maintaining a low temperature coefficient of resonant frequency, the ceramic material comprising a chemical formula of Ba_12.6Sm_27.4Ti_53.4Ta_0.6O₁₆₂.

16. The ceramic material of claim 15 wherein the ceramic material has a tungsten bronze crystal structure.

17. The ceramic material of claim 15 wherein the ceramic material has a dielectric constant of at least 60 and a temperature coefficient of resonant frequency of less than 15.

18. The ceramic material of claim 17 wherein the temperature coefficient of resonant frequency is less than 5.

19. The ceramic material of claim 15 wherein the ceramic material has no rutile or perovskite phase.

20. The ceramic material of claim 15 wherein the ceramic material has a Qf at 1 GHz of at least 8000.