Mobile communication terminal

• US 20050153755A1
• Filed: 09/24/2004
• Published: 07/14/2005
• Est. Priority Date: 01/13/2004
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Suzuki, Hiromichi, Amano, Takashi
• Granted Patent: US 7,158,820 B2
• Time in Patent Office: Days
• US Class Current: 455/575.700
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 1/245 with means for shaping the antenna pattern, e.g. in order to protect user against rf exposure
• CPC Class Codes: H01Q 5/371 Branching current paths
• CPC Class Codes: H01Q 5/378 Combination of fed elements with parasitic elements
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

A mobile communication terminal of a portable telephone is housed in a casing having a first surface. A receiver section of the portable telephone capable of generating a voice is arranged on the first surface. A two-wavelength loop antenna arranged on a plane substantially parallel to the first plane and formed of a looped line having a right section and a left section that are in symmetry with respect to an imaginary vertical symmetric line is housed in the casing. A power supply point for supplying an electric power to the loop antenna is arranged in the vicinity of the intersection between the symmetric line and the looped line.

Claims

1. A mobile communication terminal, comprising:

a casing having a first surface;

a receiver section arranged on the first surface of the casing, configured to reproduce a voice;

a two-wavelength loop antenna housed in the casing, arranged along a plane substantially parallel to the first surface of the casing, which includes a looped line that is divided by an imaginary vertical symmetric line into a right portion and a left portion that are substantially in symmetry with respect to the imaginary vertical symmetric line; and

a power supply point arranged in the vicinity of the intersection between the symmetrical line and the looped line, configured to supply an electric power to the loop antenna.

2. The mobile communication terminal according to claim 1, further comprising a ground plate arranged in the vicinity of the intersection and connected to the other terminal of the loop antenna.

3. The mobile communication terminal according to claim 1, further comprising first and second antenna components arranged on the right side and the left side of the line of the loop antenna in the positions that are substantially in symmetry with respect to the imaginary symmetric line, the length of that portion of the line of the loop antenna which includes any of the first and second antenna components and which extends from the power supply point to reach the intersection between the line of the loop antenna and the imaginary symmetric line on the opposite side of the power supply point having a length substantially equal to one wavelength.

4. The mobile communication terminal according to claim 3, wherein each of the first and second antenna components corresponds to a meander-like line, a line of a helical structure, or a dielectric element.

5. The mobile communication terminal according to claim 3, further comprising a short-circuiting line configured to form a short-circuiting between the right side section and the left side section of the loop antenna in positions that are substantially in symmetry with respect to the symmetric line.

6. The mobile communication terminal according to claim 1, wherein an antenna component is mounted to the short-circuiting line.

7. The mobile communication terminal according to claim 1, further comprising a short-circuiting line configured to form a short-circuiting between the right side section and the left side section of the line of the loop antenna in positions that are substantially in symmetry with respect to the symmetric line.

8. The mobile communication terminal according to claim 1, further comprising a parasitic element arranged in the vicinity of the power supply point such that the right portion and the left portion of the parasitic element are substantially in symmetry with respect to the symmetric line.

9. The mobile communication terminal according to claim 1, further comprising:

a power supply line having a length that is an odd number times as long as about ¼

wavelength and having one end electromagnetically coupled with one point of the line; and

a power supply point connected to the other end of the power supply line,

wherein the distance of the path from the intersection of the symmetric line and the looped line to the power supply line, the path including the electromagnetic coupling point, is an integer number times as long as about ½

wavelength.