Antenna device and portable radio communication terminal

• US 20040239575A1
• Filed: 03/17/2004
• Published: 12/02/2004
• Est. Priority Date: 07/19/2002
• Status: Active Grant

• Current Assignee: Sony Ericsson Mobile Communications Japan Incorporated (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications Japan Incorporated (Sony Group Corp.)
• Inventors: Kanayama, Yoshiki, Shoji, Hideaki, Sawamura, Masatoshi
• Granted Patent: US 7,053,848 B2
• Time in Patent Office: Days
• US Class Current: 343/770
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 13/10 Resonant slot antennas
• CPC Class Codes: H01Q 5/385 Two or more parasitic elements

Abstract

The present invention relates to an antenna device and a mobile radio communication terminal adapted for improving the performance of an antenna. The antenna device includes a radio circuit 22 for transmitting and receiving a high-frequency signal, a notch antenna 23 having a feeder 25, and a notch antenna 24 operating through electromagnetic coupling with the notch antenna 23, and a substrate 21 independent of the radio circuit 22 with respect to high frequencies. The notch antenna 23 includes a linear slit having a length of λ/4 and cut from one edge of the substrate 21 on the reverse side to the position of the radio circuit 22. The notch antenna 24 includes a linear slit having a length slightly shorter than λ/4 and cut in parallel with the notch antenna 23 from the same edge thereof at a position spaced apart by a predetermined distance d from the notch antenna 23. The present invention is applicable to a mobile telephone.

Claims

1. An antenna device comprising:

a substrate independent of a radio circuit with respect to high frequencies;

a first notch antenna in slit-shape formed on said substrate and having a feeder; and

a second notch antenna in slit-shape formed on said substrate and operating through electromagnetic coupling with said first notch antenna.

2. The antenna device according to claim 1, wherein said second notch antenna is so formed as to be different in slit length from said first notch antenna.

3. The antenna device according to claim 1, wherein said second notch antenna is formed substantially in parallel with said first notch antenna in such a manner that main polarization thereof becomes coincident with that of said first notch antenna.

4. The antenna device according to claim 1, wherein each of the slits in said first and second notch antennas is shaped into an L, zigzag or meander.

5. The antenna device according to claim 1, wherein said second notch antenna is so formed as to have two or more slits of mutually different lengths.

6. The antenna device according to claim 1, wherein the open end of said first notch antenna and the open end of said second notch antenna are connected to a common open end.

7. The antenna device according to claim 1, wherein a metallic, dielectric or magnetic member is disposed between the open end of said first notch antenna and the open end of said second notch antenna.

8. The antenna device according to claim 1, wherein a concentrated constant element consisting of a capacitor is interposed between the open end of said first notch antenna and the open end of said second notch antenna.

9. The antenna device according to claim 1, wherein said second notch antenna has a phaser to give a desired reactance value.

17. The antenna device according to claim 8, wherein said first notch antenna has, at the open end thereof, a first concentrated constant element consisting of a conductor;

and said second notch antenna has, at the open end thereof, a second concentrated constant element.

10. An antenna device comprising:

a substrate independent of a radio circuit with respect to high frequencies;

a first antenna formed on said substrate and comprising of a slit-shaped notch antenna having a feeder; and

a second antenna disposed in the vicinity of an open end of said first antenna in such a manner that the direction of main polarization thereof becomes coincident with that of said first antenna, and operating through electromagnetic coupling with said first antenna.

11. The antenna device according to claim 10, wherein said second antenna is a linear antenna shaped into a zigzag, helical, meander or loop.

12. The antenna device according to claim 10, wherein said second antenna is a notch antenna formed on another substrate different from said substrate where said first antenna is formed.

13. A mobile radio communication terminal comprising:

a substrate independent of a radio circuit with respect to high frequencies;

a first notch antenna in slit-shape formed on said substrate and having a feeder;

a second notch antenna in slit-shape formed on said substrate and operating through electromagnetic coupling with said first notch antenna; and

a body for housing said substrate.

14. The mobile radio communication terminal according to claim 13, wherein said body comprises of a first body for housing said substrate, and a second body openable and closable in regard to said first body, wherein the open ends of said first and second notch antennas are disposed in a portion of said first body that projects from said second body when said first and second bodies are in a closed state.

15. A mobile radio communication terminal comprising:

a substrate independent of a radio circuit with respect to high frequencies;

a first antenna formed on said substrate and comprising of a slit-shaped notch antenna having a feeder;

a second antenna disposed in the vicinity of an open end of said first antenna in such a manner that the direction of main polarization thereof becomes coincident with that of said first antenna, and operating through electromagnetic coupling with said first antenna; and

a body for housing said first and second antennas.

16. The mobile radio communication terminal according to claim 15, wherein said body comprises of a first body for housing said substrate, and a second body openable and closable in regard to said first body, wherein the open end of said first antenna and said second antenna are disposed in a portion of said first body that projects from said second body when said first and second bodies are in a closed state.