Modified Z-type hexagonal ferrite materials with enhanced resonant frequency

Patent metadata

Field	Value
Publication number	US-10027035-B2
Application number	US-201514804588-A
Country	US
Kind code	B2
Filing date	Jul 21, 2015
Priority date	Sep 30, 2014
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

Disclosed herein are embodiments of modified z-type hexagonal ferrite materials having improved properties that are advantageous for radiofrequency applications, in particular high frequency ranges for antennas and other devices. Atomic substitution of strontium, aluminum, potassium, and trivalent ions can be used to replace certain atoms in the ferrite crystal structure to improve loss factor at high frequencies.

First claim

What is claimed is:

1. A high resonant-frequency material composition comprising:
an enhanced z-type hexagonal ferrite having some barium atoms substituted for strontium atoms and some iron atoms substituted for aluminum atoms, the enhanced z-type hexagonal ferrite having a formula Ba 3-x Sr x Co 2 Fe 24-y Al y O 41 , x being 0<x≤1.5 and y being 0<y≤0.9, and having a resonant frequency of over about 500 MHz, the material being formed by a sintering process.

2. The high resonant-frequency material of claim 1 wherein x=1.5 and y=0.9.

3. The high resonant-frequency material of claim 1 wherein x=1.5 and y=0.3.

4. The high resonant-frequency material of claim 1 wherein the enhanced z-type hexagonal ferrite has a resonant frequency over 1 GHz.

5. A radio frequency device comprising the high resonant-frequency material of claim 1 .

6. A high frequency antenna comprising the high resonant-frequency material composition of claim 1 .

7. The high resonant-frequency material of claim 1 wherein the hexagonal ferrite material has a resonant frequency greater than 700 MHz.

8. The high resonant-frequency material of claim 1 wherein the hexagonal ferrite material has a resonant frequency greater than 900 MHz.

9. A method of forming a radiofrequency device, the method comprising:
blending a mixture of precursor materials including barium, cobalt, iron, and oxygen;
drying, heating, milling, and pressing the mixture;
sintering the pressed particles to form a hexagonal ferrite material having a composition of Ba 3-x Sr x Co 2 Fe 24-y Al y O 41 , x being 0<x≤1.5 and y being 0<y≤0.9; and
forming a radiofrequency device from the hexagonal ferrite material.

10. The method of claim 9 wherein the hexagonal ferrite material has a resonant frequency greater than 900 MHz.

11. The method of claim 9 wherein the radiofrequency device is an antenna.

12. The method of claim 9 wherein the hexagonal ferrite material has a resonant frequency greater than 1 GHz.

13. The method of claim 9 wherein x =1.5 and y =0.9.

14. The method of claim 9 wherein the hexagonal ferrite material has a resonant frequency greater than 700 MHz.

15. A circulator for a radiofrequency device, the circulator comprising:
an enhanced z-type hexagonal ferrite having some barium atoms substituted for strontium atoms and some iron atoms substituted for aluminum atoms, the enhanced z-type hexagonal ferrite having a formula Ba 3-x Sr x Co 2 Fe 24-y Al y O 41 , x being 0<x≤1.5 and y being 0<y≤0.9, and having a resonant frequency of over about 500 MHz, the material being formed by a sintering process.

16. The circulator of claim 15 wherein the hexagonal ferrite material has a resonant frequency greater than 1 GHz.

17. The circulator of claim 15 wherein x =1.5 and y =0.9.

18. The circulator of claim 15 wherein x =1.5 and y =0.3.

19. The circulator of claim 15 wherein the hexagonal ferrite material has a resonant frequency greater than 700 MHz.

20. The circulator of claim 15 wherein the hexagonal ferrite material has a resonant frequency greater than 900 MHz.

Assignees

• Skyworks Solutions Inc

Inventors

• Hill Michael David

Classifications

• C04B35/62655

  Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying · CPC title

• C04B2235/96

  Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance · CPC title

• C04B2235/5445

  submicron sized, i.e. from 0,1 to 1 micron · CPC title

• H01F41/0246

  Manufacturing of magnetic circuits by moulding or by pressing powder (magnetic cores made by moulding or by pressing powder H01F27/255; soft magnetic particles H01F1/20, H01F1/36) · CPC title

• H01F1/348 Primary

  Hexaferrites with decreased hardness or anisotropy, i.e. with increased permeability in the microwave (GHz) range, e.g. having a hexagonal crystallographic structure · CPC title