Chip antenna and method of making same

• US 5,892,489 A
• Filed: 04/01/1997
• Issued: 04/06/1999
• Est. Priority Date: 04/05/1996
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Asakura, Kenji, Suesada, Tsuyoshi, Kanba, Seiji, Tsuru, Teruhisa, Mandai, Harufumi
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US08/831,075
• Time in Patent Office: 735 Days
• Field of Search: 343/895, 343/702, 343/700 MS, 343/873, 343/872
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/362 for broadside radiating helical antennas
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142

Abstract

A chip antenna in which desired antenna characteristics can be obtained without restricting the type of at least one of a dielectric material and a magnetic material used for a base member of the antenna, as well as the type of metal material used for a conductor, or without limiting the sintering conditions of the above-described materials. The chip antenna includes a rectangular-prism-shaped base member having a mounting surface. A conductor, e.g. silver, is spirally wound inside the base member. A feeding terminal is formed over surfaces of the base member so as to feed power to the conductor. One end of the conductor is extended to a surface of the base member to form a feeding section, which is connected to the feeding terminal. The other end of the conductor serves as a free end within the base member. The base member is produced by laminating mixture layers made from a mixture of glass essentially consisting of borosilicate having a softening point of approximately 700° C. and ceramic (relative dielectric constant: 60) essentially consisting of barium oxide, neodymium oxide and titanium oxide having a sintering temperature of approximately 1300° C.

Claims

1. A chip antenna comprising:

a base member comprising at least one of a dielectric material and a magnetic material;

at least one conductor formed at least one of on a surface of the base member and inside said base member; and

at least one feeding terminal disposed on a surface of said base member, for applying voltage to said conductor;

said base member comprising at least one of a glass having a melting point lower than the melting point of said conductor, a low-temperature sintering ceramic, and a mixture of glass and ceramic.

2. The chip antenna of claim 1, wherein the base member comprises a mixture comprising glass comprising borosilicate having a softening point at approximately 700°

C. and ceramic comprising barium oxide, neodymium oxide and titanium oxide having a sintering temperature at approximately 1300°

C., said mixture having a sintering temperature range of approximately 800°

to 1000°

C.

3. The chip antenna of claim 2, wherein the base member comprises a plurality of layers of said mixture with said conductor deposited between said layers in sections, the sections being attached together and taken as a whole comprising said conductor.

4. The chip antenna of claim 3, wherein a section of the conductor is deposited on a mixture layer, followed by a further mixture layer covering a portion of said conductor section, followed by a further conductor section connected to the first conductor section, and covering said further mixture layer, with at least one further mixture layer and at least one further conductor section being deposited so that a predetermined plurality of layers are provided with conductor sections therebetween in said base member.

5. The chip antenna of claim 4, further wherein each section of the conductor is dried prior to applying a further mixture layer.

6. The chip antenna of claim 5, wherein the base member having the conductor therein is heated at a temperature of approximately 300°

C. in air to burn an organic component and then heated at a temperature of approximately 800°

C. to sinter it.

7. The chip antenna of claim 6, wherein the feeding terminal is attached to the base member in contact with the conductor, with the base member thereafter being baked.

8. The chip antenna of claim 1, wherein the conductor comprises at least one of copper, gold and silver.

9. The chip antenna of claim 1, wherein the conductor has a rectangular cross-section.

10. The chip antenna of claim 1, wherein the conductor has at least one linear portion in cross-section.

11. The chip antenna of claim 1, wherein the conductor is formed as a spiral.

12. The chip antenna of claim 1, wherein the glass comprises at least one of cordierite, mullite, anorthite, celsian, spine, gahnite, dolomite, petalite, and derivatives thereof.

13. The chip antenna of claim 1, wherein the ceramic comprises at least one of tin barium borate, zirconium barium borate, alumina, cristobalite, quartz, corundum, mullite, zirconia and cordierite.

14. The chip antenna of claim 1, wherein the conductor has a meandering shape.

15. The chip antenna of claim 1, wherein the conductor is disposed on a surface of the base member.

16. The chip antenna of claim 1, wherein the conductor is disposed partly in the base member and partly on a surface of the base member.

17. The chip antenna of claim 1, wherein there are provided a plurality of conductors.

18. The chip antenna of claim 17, wherein the plurality of conductors provide the chip antenna with a plurality of resonant frequencies.

19. The chip antenna of claim 1, wherein the base member is one of a rectangular prism, cube, cylinder, pyramid, cone and sphere.

20. The chip antenna of claim 1, wherein one end of the conductor is coupled to the feeding terminal and a second end comprises a free end.

21. A method of making a chip antenna comprising the steps of:

forming a base member comprising at least one of a dielectric material and a magnetic material;

forming at least one conductor at least one of on a surface of the base member and inside said base member; and

disposing at least one feeding terminal on a surface of said base member, for applying voltage to said conductor;

said step of forming a base member further comprising;

forming said base member from at least one of a glass having a melting point lower than the melting point of said conductor, a low-temperature sintering ceramic, and a mixture of glass and ceramic.

22. The method of claim 21, wherein the step of forming the base member comprises providing a mixture comprising glass comprising borosilicate having a softening point at approximately 700°

C. and ceramic comprising barium oxide, neodymium oxide and titanium oxide having a sintering temperature at approximately 1300°

C., said mixture having a sintering temperature range of approximately 800°

to 1000°

C.

23. The method of claim 22, wherein the step of forming the base member comprises providing a plurality of layers of said mixture with said conductor deposited between said layers in sections, the sections being attached together and taken as a whole comprising said conductor.

24. The antenna of claim 23, wherein the steps of forming the base member and the conductor comprise the step of depositing a section of the conductor on a mixture layer, followed by forming a further mixture layer covering a portion of said conductor section, followed by depositing a further conductor section connected to the first conductor section and covering said further mixture layer, with said steps of forming a further mixture layer and a further conductor section being repeated a predetermined plurality of times until said base member with the conductor therein is formed.

25. The method of claim 24, further comprising drying each section of the conductor prior to applying a further mixture layer.

26. The method of claim 25, further comprising heating the base member having the conductor therein at a temperature of approximately 300°

C. in air to burn an organic component and then heating at a temperature of approximately 800°

C. to sinter it.

27. The method of claim 26, further comprising attaching the feeding terminal to the base member in contact with the conductor, and thereafter baking the base member.

28. The method of claim 21, wherein the step of forming at least one conductor comprises forming the conductor of at least one of copper, gold and silver.

29. The method of claim 21, wherein the step of forming the at least one conductor comprises forming the conductor with a rectangular cross-section.

30. The method of claim 21, wherein the step of forming the at least one conductor comprise forming the conductor with at least one linear portion in cross-section.

31. The method of claim 21, wherein the step of forming the at least one conductor comprises forming the conductor as a spiral.

32. The method of claim 21, wherein the step of forming the base member comprises forming the base member of glass comprising at least one of cordierite, mullite, anorthite, celsian, spine, gahnite, dolomite, petalite, and derivatives thereof.

33. The method of claim 21, wherein the step of forming the base member comprises forming the base member of ceramic comprising at least one of tin barium borate, zirconium barium borate, alumina, cristobalite, quartz, corundum, mullite, zirconia and cordierite.

34. The method of claim 21, wherein the step of forming the conductor comprises forming the conductor with a meandering shape.

35. The method of claim 21, wherein the step of forming the conductor comprises forming the conductor on a surface of the base member.

36. The method of claim 21, wherein the step of forming the conductor comprises forming the conductor partly in the base member and partly on a surface of the base member.

37. The method of claim 21, wherein the step of forming the conductor comprises forming the conductor as a plurality of conductors.

38. The method of claim 37, wherein the plurality of conductors provide the chip antenna with a plurality of resonant frequencies.

39. The method of claim 21, wherein the step of forming the base member comprises forming the base member as one of a rectangular prism, cube, cylinder, pyramid, cone and sphere.

40. The method of claim 21, wherein the step of forming the conductor comprises forming one end of the conductor coupled to the feeding terminal and a second end as a free end.