Surface-mounted antenna and communications apparatus comprising same

• US 20030006936A1
• Filed: 06/14/2002
• Published: 01/09/2003
• Est. Priority Date: 06/15/2001
• Status: Active Grant

• Current Assignee: Hitachi Metals (Thailand) Ltd.
• Original Assignee: Hitachi Metals (Thailand) Ltd.
• Inventors: Takaki, Yasunori, Aoyama, Hiroyuki, Kikuchi, Keiko, Hagiwara, Hidetoshi
• Granted Patent: US 6,873,291 B2
• Time in Patent Office: Days
• US Class Current: 343/700MS
• CPC Class Codes: H01Q 1/243 with built-in 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 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A surface-mounted antenna comprising a substrate made of a high-dielectric constant material having a dielectric constant ∈_r of 6 or more, a ribbon-shaped radiation electrode having one end which is grounded and the other end which is open, a grounding electrode connected or capacitance-coupled to one end of the radiation electrode, and a current-feeding electrode in a portal shape formed on a side surface separate from the radiation electrode with a gap; the current-feeding electrode having a current-feeding portion at one end, a grounding portion at the other end, and a portion substantially in alignment with the radiation electrode between them; and the length of the aligning portion, a gap width or a portal shape being able to be properly set such that capacitance owned by the current-feeding electrode and inductance can be adjusted for easily achieving impedance matching.

Claims

1. A surface-mounted antenna comprising a substrate made of a dielectric or magnetic material, a radiation electrode formed on at least an upper surface of said substrate, a grounding electrode formed on said substrate such that said grounding electrode is directly connected or capacitance-coupled to one end of said radiation electrode, and a current-feeding electrode formed on at least a side surface of said substrate such that said current-feeding electrode faces said radiation electrode via a gap;

said current-feeding electrode having a current-feeding point at one end and a grounding point at the other end, as well as a portion for achieving impedance matching by capacitance and inductance between said current-feeding point and said grounding point; and

an area ratio of said grounding electrode in a bottom surface of said substrate being 30% or less.

2. A surface-mounted antenna comprising a substrate made of a dielectric or magnetic material, a radiation electrode formed on at least an upper surface of said substrate, a grounding electrode formed on said substrate such that said grounding electrode is directly connected or capacitance-coupled to one end of said radiation electrode, and a current-feeding electrode formed on at least a side surface of said substrate such that said current-feeding electrode faces said radiation electrode via a gap;

said current-feeding electrode being in a portal shape having a current-feeding portion at one end and a grounding portion at the other end, as well as a portion in alignment with said radiation electrode via a gap between them.

5. The surface-mounted antenna according to claim 2, wherein an area ratio of said grounding electrode in a bottom surface of said substrate is 30% or less.

6. The surface-mounted antenna according to claim 2, wherein at least part of said current-feeding electrode is in a shape of a meander, rectangular U, L or a crank.

7. The surface-mounted antenna according to claim 2, wherein said current-feeding electrode is formed on a side surface of said substrate such that it faces an open tip end of said radiation electrode with a gap.

8. The surface-mounted antenna according to claim 2, wherein said current-feeding electrode has a current-feeding portion positioned near an open tip end of said radiation electrode.

9. The surface-mounted antenna according to claim 2, wherein at least part of said radiation electrode extends from one end of said substrate toward the other end thereof in a longitudinal direction with its width narrowing substantially continuously and/or stepwise.

10. The surface-mounted antenna according to claim 2, wherein said radiation electrode extends to an upper surface through a side surface different from a side surface on which said current-feeding electrode is formed.

11. The surface-mounted antenna according to claims 2, wherein the bottom surface of said substrate has substantially no grounding electrode in at least an area under a tip end portion of said radiation electrode formed on an upper surface of said substrate.

12. The surface-mounted antenna according to claim 2, wherein said radiation electrode has a bent portion in a shape of a meander, rectangular U, L or a crank.

13. The surface-mounted antenna according to claim 12, wherein said radiation electrode and/or said current-feeding electrode has round corners.

14. The surface-mounted antenna according to claim 2, wherein said antenna further comprises a second grounding electrode opposing the other end of said radiation electrode via a gap.

16. The surface-mounted antenna according to claim 15, wherein said current-feeding portion of said current-feeding electrode is positioned near an open tip end of said radiation electrode, while said grounding portion of said current-feeding electrode is positioned near a substrate end on the opposite side to said grounding electrode.

18. The communications apparatus according to claim 17, wherein said grounding electrode formed on said surface-mounted antenna on the opposite side of said ground conductor of said circuit board is arranged near a corner of said circuit board, and said grounding electrode is connected to a conductor of said circuit board by a linear conductor.

3. A surface-mounted antenna comprising a substrate made of a dielectric or magnetic material, a radiation electrode formed on at least an upper surface of said substrate, a grounding electrode formed on said substrate such that said grounding electrode is directly connected or capacitance-coupled to one end of said radiation electrode, and a current-feeding electrode formed on at least a side surface of said substrate such that said current-feeding electrode faces said radiation electrode via a gap;

said current-feeding electrode being constituted by two L-shaped electrodes formed on the opposing side surfaces of said substrate, which are connected via one I-shaped electrode formed on an end surface of said substrate;

one L-shaped electrode having a current-feeding portion at one end;

the other L-shaped electrode having a grounding portion at one end; and

said I-shaped electrode being a portion in alignment with said radiation electrode, whereby said current-feeding electrode is in a portal shape.

4. The surface-mounted antenna according to claim 3, wherein said current-feeding electrode is constituted by first and second electrodes formed on the opposing side surfaces of said substrate, which is connected via one I-shaped electrode formed on an end surface of said substrate;

the first electrode having a current-feeding portion at one end, the second electrode having a grounding portion at one end, and said I-shaped electrode being said aligning portion, so that said current-feeding electrode is in a portal shape; and

said radiation electrode having a grounding electrode portion formed on an end surface, or on an end surface and opposing side surfaces, of said substrate.

15. A surface-mounted antenna comprising a substrate made of a dielectric or magnetic material, a ribbon-shaped radiation electrode formed on said substrate, a grounding electrode formed on said substrate such that said grounding electrode is directly connected or capacitance-coupled to one end of said radiation electrode, and a current-feeding electrode formed on at least a side surface of said substrate separate from said radiation electrode with a desired gap;

said radiation electrode being in a portal shape as a whole comprising an electrode portion formed on one side surface of said substrate in a longitudinal direction, which is connected to an L-shaped electrode portion formed on an upper surface of said substrate;

said current-feeding electrode comprising a current-feeding portion and a grounding portion each extending substantially vertically on the other side surface of said substrate, and an aligned portion extending between said current-feeding portion and said grounding portion substantially in parallel with said radiation electrode via said gap;

an area ratio of said grounding electrode in a bottom surface of said substrate being 30% or less; and

the shape and positional relation of said current-feeding electrode and said radiation electrode being modified to adjust capacitance and inductance for impedance matching.

17. A communications apparatus comprising an antenna apparatus having a surface-mounted antenna comprising a substrate made of a dielectric or magnetic material, a radiation electrode formed on at least an upper surface of said substrate in a longitudinal direction, a grounding electrode formed on said substrate such that said grounding electrode is directly connected or capacitance-coupled to one end of said radiation electrode, and a current-feeding electrode formed on at least a side surface of said substrate such that said current-feeding electrode faces said radiation electrode via a gap;

said current-feeding electrode being in a portal shape having a current-feeding portion at one end and a grounding portion at the other end, as well as a portion in alignment with said radiation electrode via a gap between them;

said surface-mounted antenna being mounted onto said circuit board; and

said surface-mounted antenna being mounted onto an area of a circuit board free from a ground conductor, such that said substrate is aligned in a longitudinal direction with an edge of said ground conductor with a gap, and that said current-feeding electrode is positioned on the side of said ground conductor.