Chip antenna and a method for adjusting frequency of the same

• US 6,064,351 A
• Filed: 03/04/1998
• Issued: 05/16/2000
• Est. Priority Date: 03/05/1997
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Tsuru, Teruhisa, Mandai, Harufumi
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): VANNUCCI, JAMES
• Application Number:
  US09/034,416
• Time in Patent Office: 804 Days
• Field of Search: 343/873, 343/702, 343/700 MS, 343/895
• US Class Current: 343/873
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• 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
• CPC Class Codes: H01Q 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system

Abstract

A chip antenna 10 is formed of a rectangular prism substrate 11 made of a dielectric material (relative magnetic permeability: approximately 6.1) essentially consisting of barium oxide, aluminum oxide, and silica. A conductor 12 is spirally wound within the substrate 11 in the longitudinal direction of the substrate 11. A power feeding terminal 13 is formed on a surface of the substrate 11 and is connected to one end of the conductor 12 in order to apply a voltage to the conductor 12. A trimming electrode 14 generally formed in the shape of a rectangle is formed on a surface of the substrate 11 and is connected to the other end of the conductor 12. With the above configuration, a capacitive coupling is generated between the trimming electrode 14 and a ground (not shown) of a mobile communication unit on which the chip antenna 10 is mounted, and between the trimming electrode 14 and the conductor 12.

Claims

1. A chip antenna comprising:

a substrate made of at least one of a dielectric material and a magnetic material;

at least one conductor disposed at least one of within said substrate and on a surface of said substrate;

at least one power feeding terminal disposed on a surface of said substrate and connected to one end of said conductor for applying a voltage to said conductor; and

a trimming electrode disposed at least one of within said substrate and on a surface of said substrate and connected to the other end of said conductor; and

further wherein

the substrate comprises a plurality of layers stacked on top of each other, the stacked layers having a direction normal to the stacked layers, the at least one conductor disposed spirally within the substrate or on the surface of the substrate and having a spiral axis extending perpendicular to the direction normal to the stacked layers.

2. The chip antenna according to claim 1, further comprising a resin layer covering said trimming electrode.

3. The chip antenna according to claim 1, wherein:

said substrate is formed by laminating a plurality of said stacked layers together, the layers each having a major surface; and

said trimming electrode is disposed on one of the major surfaces of said layers.

4. A method for adjusting a frequency of a chip antenna, the chip antenna comprising a substrate made of at least one of a dielectric material and a magnetic material;

at least one conductor disposed at least one of within said substrate and on a surface of said substrate;

at least one power feeding terminal disposed on a surface of said substrate and connected to one end of said conductor for applying a voltage to said conductor; and

a trimming electrode disposed at least one of within said substrate and on a surface of said substrate and connected to the other end of said conductor; and

further wherein the substrate comprises a plurality of layers stacked on top of each other, the stacked layers having a direction normal to the stacked layers, the at least one conductor disposed spirally within the substrate or on the surface of the substrate and having a spiral axis extending perpendicular to the direction normal to the stacked layers;

the method comprising the step of;

changing an area of said trimming electrode.

5. The method according to claim 4, wherein:

the area of said trimming electrode is changed by using a laser.