Temperature insensitive dielectric constant garnets

Patent metadata

Field	Value
Publication number	US-10773972-B2
Application number	US-201715645122-A
Country	US
Kind code	B2
Filing date	Jul 10, 2017
Priority date	Jul 13, 2016
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

Embodiments of synthetic garnet materials having advantageous properties, especially for below resonance frequency applications, are disclosed herein. In particular, embodiments of the synthetic garnet materials can have high Curie temperatures and dielectric constants while maintaining low magnetization. These materials can be incorporated into isolators and circulators, such as for use in telecommunication base stations.

First claim

What is claimed is:

1. A temperature-insensitive ceramic material comprising bismuth incorporated into a crystal structure of a garnet to form a synthetic garnet having a dielectric constant of above 24 and a Curie temperature of above 200° C. with an absence of any aluminum occurring within the synthetic garnet, the synthetic garnet having a composition selected from the group consisting of: Bi 1.4 Ca 1.6 In 0.36 Zr 0.0156 V 0.7922 Fe 3.8122 O 11.97 . Bi 1.4 Ca 1.6 In 0.32 Zr 0.0312 V 0.7844 Fe 3.8444 O 11.97 , Bi 1.4 Ca 1.6 In 0.28 Zr 0.0468 V 0.7766 Fe 3.8766 O 11.97 , Bi 1.4 Ca 1.6 In 0.24 Zr 0.0624 V 0.7688 Fe 3.9088 O 11.97 , Bi 1.4 Ca 1.6 In 0.20 Zr 0.078 V 0.7610 Fe 3.9410 O 11.97 ; and Bi 1.4 Ca 1.6 In 0.16 Zr 0.0936 V 0.7532 Fe 3.9732 O 11.97 .

2. The temperature-insensitive ceramic material of claim 1 wherein the synthetic garnet has a dielectric constant of above 25.

3. The temperature-insensitive ceramic material of claim 1 wherein the synthetic garnet has a Curie temperature of above 220° C.

4. The temperature-insensitive ceramic material of claim 1 wherein the synthetic garnet has a 3 dB linewidth of below 60.

5. A temperature insensitive circulator or isolator comprising:
an aluminum-free synthetic garnet having a dielectric constant of above 24, a 3 dB linewidth of below 100, a Curie temperature of above 200° C., and a composition Y 3-x-y Bi x Ca y Zr y Fe 5-y O 12 , x being between 0 and 1.8 and y being between 0 and 1.0.

6. A base station incorporating the temperature insensitive circulator or isolator of claim 5 .

7. The temperature insensitive circulator or isolator of claim 5 wherein the temperature insensitive circulator or isolator is used in below-resonance frequency applications.

8. The temperature insensitive circulator or isolator of claim 5 wherein the aluminum-free synthetic garnet has a Curie temperature of above 220° C.

9. The temperature insensitive circulator or isolator of claim 5 wherein the aluminum-free synthetic garnet has greater than 1.4 units of bismuth.

10. The temperature-insensitive ceramic material of claim 1 wherein the synthetic garnet has a Curie temperature of above 230° C.

11. A circulator or isolator formed from the synthetic garnet of the temperature insensitive ceramic material of claim 1 .

12. A base station incorporating the circulator or isolator of claim 11 .

13. A temperature-insensitive ceramic material comprising bismuth incorporated into a crystal structure of a garnet to form a synthetic garnet having a dielectric constant of above 24 and a Curie temperature of above 200° C. with an absence of any aluminum occurring within the synthetic garnet, the synthetic garnet having a composition selected from the group consisting of: Bi 1.4 Ca 1.6 In 0.36 Zr 0.0156 V 0.7922 Fe 3.8122 O 11.97 . Bi 1.4 Ca 1.6 In 0.32 Zr 0.0312 V 0.7844 Fe 3.8444 O 11.97 , Bi 1.4 Ca 1.6 In 0.28 Zr 0.0468 V 0.7766 Fe 3.8766 O 11.97 , Bi 1.4 Ca 1.6 In 0.24 Zr 0.0624 V 0.7688 Fe 3.9088 O 11.97 , Bi 1.4 Ca 1.6 In 0.20 Zr 0.078 V 0.7610 Fe 3.9410 O 11.97 , Bi 1.4 Ca 1.6 In 0.16 Zr 0.0936 V 0.7532 Fe 3.9732 O 11.97 , Bi 1.4 Ca 1.6 In 0.12 Zr 0.1092 V 0.7454 Fe 4.0054 O 11.97 , Bi 1.4 Ca 1.6 In 0.08 Zr 0.1248 V 0.7376 Fe 4.0376 O 11.97 , and Bi 1.4 Ca 1.6 In 0.04 Zr 0.1404 V 0.7298 Fe 4.0698 O 11.97 .

14. The temperature-insensitive ceramic material of claim 13 wherein the synthetic garnet has a dielectric constant of above 25.

15. The temperature-insensitive ceramic material of claim 13 wherein the synthetic garnet has a Curie temperature of above 220° C.

16. The temperature-insensitive ceramic material of claim 13 wherein the synthetic garnet has a Curie temperature of above 230° C.

17. A circulator or isolator formed from the synthetic garnet of the temperature insensitive ceramic material of claim 13 .

18. A base station incorporating the circulator or isolator of claim 17 .

Assignees

• Skyworks Solutions Inc

Inventors

• Cruickshank David Bowie
• Hill Michael David

Classifications

• C01G49/009

  Compounds containing iron, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• G02F1/0036 Primary

  Magneto-optical materials · CPC title

• C04B35/2675

  Other ferrites containing rare earth metals, e.g. rare earth ferrite garnets · CPC title

• G02F2203/60

  Temperature independent · CPC title

• C04B2235/6025

  Tape casting, e.g. with a doctor blade · CPC title