Antenna

• US 6,441,789 B1
• Filed: 04/18/2001
• Issued: 08/27/2002
• Est. Priority Date: 10/29/1998
• Status: Expired due to Fees

• Current Assignee: Kouji Sasano
• Original Assignee: Kouji Sasano
• Inventors: Sasano, Kouji
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): Clinger, James
• Application Number:
  US09/807,883
• Time in Patent Office: 496 Days
• Field of Search: 343/702, 343/901, 343/715, 343/900, 343/725, 343/729, 455/90
• US Class Current: 343/702
• CPC Class Codes: H01Q 1/244 extendable from a housing along a given path
• CPC Class Codes: H01Q 9/16 with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole H01Q9/44 takes precedence
• CPC Class Codes: H01Q 9/30 with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence

Abstract

A retractable antenna for mobile devices exhibits a high gain regardless of whether it is extended or retracted in the device. A λ/4 antenna element is retractably housed in a metal tube λ/4 long. A switching mechanism is provided so that the radio frequency power feed condition varies according to whether the λ/4 antenna element is extended or is retracted in the tube. The metal tube of length λ/4 is fed the radio frequency power of polarity opposite to that of the antenna element when the antenna element is extended, so that the tube and the antenna element function together as a dipole antenna. When the antenna is retracted into the tube, the radio frequency power is not fed to the antenna element, and the metal tube functions as a λ/4 antenna element.

Claims

1. An antenna, comprising:

a λ

/4 antenna element retractably coupled to a case of a portable device;

a conductive structure having a cylindrical shape and a length of λ

/4 for coaxially housing said antenna element when the antenna element is retracted in the device;

a first insulator having a cylindrical shape with a first central hole for slidably supporting said antenna element in said first central hole, said first insulator being provided on an upper end of said conductive structure;

a second insulator having a cylindrical shape with a second central hole for connection with a lower end of said antenna element, said second insulator being provided on a lower end of said conductive structure; and

a radio frequency power feed conductor of cylindrical shape with a third central hole, said radio frequency power feed conductor being connected to an inner side of said first cylindrical insulator in sliding contact with said antenna element through said first central hole, and being insulated from said conductive structure, whereby;

one pole of a radio frequency power is connected to said radio frequency power feed conductor; and

another pole of the radio frequency power is connected to an upper end of said conductive structure.

2. An antenna, comprising:

a λ

/4 antenna element retractably coupled to a case of a portable device;

a conductive structure having a cylindrical shape and a length of λ

/4 for coaxially housing said antenna element when the antenna element is retracted in the device;

an insulator having a cylindrical shape with a first central hole for slidably supporting said antenna element in said first central hole, said insulator being provided on an upper end of said conductive structure;

a conductor having a cylindrical shape with a second central hole for connection with a lower end of said antenna element, said conductor being provided on a lower end of said conductive structure; and

a radio frequency power feed conductor of cylindrical shape with a third central hole, said radio frequency power feed conductor being connected to an inner side of said insulator in sliding contact with said antenna element through said first central hole, and being insulated from said conductive structure, whereby;

one pole of the radio frequency power is connected to said radio frequency power feed conductor; and

another pole of the radio frequency power is connected to an upper end of said conductive structure.

3. An antenna, comprising:

a λ

/4 antenna element retractably coupled to a case of a portable device;

a conductive structure having a semi-cylindrical shape and a length of λ

/4 for coaxially housing said antenna element when the antenna element is retracted in the device;

an insulator having a cylindrical shape with a first central hole for slidably supporting said antenna element in said first central hole, said insulator being provided on an upper end of said conductive structure;

a conductor having a cylindrical shape with a second central hole for connection with a lower end of said antenna element, said conductor being provided on a lower end of said conductive structure; and

a radio frequency power feed conductor of cylindrical shape with a third central hole, said radio frequency power feed conductor being connected to an inner side of said insulator in sliding contact with said antenna element through said first central hole, and being insulated from said conductive structure, whereby;

one pole of the radio frequency power is connected to said radio frequency power feed conductor; and

another pole of the radio frequency power is connected to an upper end of said conductive structure.

4. An antenna, comprising:

a λ

/4 antenna element retractably coupled to a case of a portable device;

two conductive plates having a partially cylindrical shape and a length of λ

/4, said plates being arranged in parallel to said antenna element when the antenna element is retracted in the device;

an insulator having a cylindrical shape with a first central hole for slidably supporting said antenna element in said first central hole, said insulator being provided on an upper end of said two conductive plates;

a conductor having a cylindrical shape with a second central hole for connection with a lower end of said antenna element, said conductor being provided on a lower end of said two conductive plates; and

a radio frequency power feed conductor of cylindrical shape with a third central hole, said radio frequency power feed conductor being connected to an inner side of said insulator in sliding contact with said antenna element through said first central hole, and being insulated from said two conductive plates, whereby;

one pole of the radio frequency power is connected to said radio frequency power feed conductor; and

another pole of the radio frequency power is connected to an upper end of said two conductive plates.

5. An antenna, comprising:

a λ

/4 antenna element retractably coupled to a case of a portable device;

a conductive plate having a length of λ

/4, said plate being arranged in parallel to said antenna element when the antenna element is retracted in the device;

an insulator having a cylindrical shape with a first central hole for slidably supporting said antenna element in said first central hole, said insulator being provided on an upper end of said conductive plate;

a conductor having a cylindrical shape with a second central hole for connection with a lower end of said antenna element, said conductor being provided on a lower end of said conductive plate; and

a radio frequency power feed conductor of cylindrical shape with a third central hole, said radio frequency power feed conductor being connected to an inner side of said insulator in sliding contact with said antenna element through said first central hole, and being insulated from said conductive plate, whereby;

one pole of the radio frequency power is connected to said radio frequency power feed conductor; and

another pole of the radio frequency power is connected to an upper end of said conductive plate.

6. An antenna according to claim 5, wherein said conductive plate is a metal plate.

7. An antenna according to claim 5, wherein said conductive plate is a conductive film.

8. An antenna comprising a cylindrical λ

/4 antenna element disposed around an internal conductor of a coaxial radio frequency power feeder, and a cylindrical λ

/4 outer tube disposed around an external conductor of said coaxial power feeder;

wherein a pole of a radio frequency power source is connected to a base of said antenna element via said internal conductor when the antenna element is extended; and

wherein another pole of the radio frequency power source is connected to an upper end of said outer tube via said external conductor, such that radio frequency power is fed to said outer tube via said internal conductor from one end of the radio frequency power source when the antenna element is retracted in the device.

9. An antenna comprising a cylindrical λ

/4 antenna element disposed around an internal conductor of a coaxial radio frequency power feeder, and a λ

/4 ground disposed around an external conductor of said coaxial radio frequency power feeder;

wherein a pole of a radio frequency power source is connected to a base of said antenna element via said internal conductor and another pole of the radio frequency power source is connected to an upper end of said ground via said external conductor when the antenna element is extended; and

wherein the radio frequency power is fed from a single pole of the radio frequency power source to said ground via said internal conductor when the antenna element is retracted in the device.

10. An antenna comprising:

a λ

/4 antenna element retractably coupled to a portable device;

a conductive structure having a length of λ

/4 and adapted for alignment with said antenna element when the antenna element is retracted in the device;

an insulating member for slidably supporting the antenna element in alignment with said conductive structure;

a first conductor member adapted for electrical connection with said antenna element when the antenna element is extended from the device;

a second conductor member electrically coupled to said conductive structure and adapted for electrical connection with said antenna element when the antenna element is retracted into the device; and

a radio-frequency device with a first pole connected to said first conductor and a second pole connected to said conductive structure.

11. The antenna of claim 10, wherein said conductive structure includes a tube.

12. The antenna of claim 10, wherein said conductive structure includes a semi-cylindrical tube section.

13. The antenna of claim 10, wherein said conductive structure includes two partially cylindrical tube sections.

14. The antenna of claim 10, wherein said conductive structure includes a plate.