Double resonance antenna and antenna for portable radio

• US 20040246186A1
• Filed: 02/09/2004
• Published: 12/09/2004
• Est. Priority Date: 06/10/2002
• Status: Active Grant

• Current Assignee: Nippon Antena Kabushiki Kaisha (Nippon Antenna Company Limited)
• Original Assignee: Nippon Antena Kabushiki Kaisha (Nippon Antenna Company Limited)
• Inventors: Shimabara, Masataka
• Granted Patent: US 7,023,388 B2
• Time in Patent Office: Days
• US Class Current: 343/702
• CPC Class Codes: H01Q 1/242 specially adapted for hand-held use
• CPC Class Codes: H01Q 1/244 extendable from a housing along a given path
• 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 5/371 Branching current paths
• CPC Class Codes: H01Q 5/378 Combination of fed elements with parasitic elements

Abstract

With the object of forming a compact antenna that operates in a plurality of frequency bands, the pattern of an antenna element 14 that can resonate in a plurality of frequency bands is formed on the outer circumferential surface of an antenna bobbin 12. A parasitic conductor 11 is inserted into an accommodating hole which is formed substantially along the central axis of this antenna bobbin 12. As a result, an antenna that operates favorably in the frequency bands of AMPS, PCS and GPS can be obtained.

Claims

1. A multiple resonance antenna comprising:

an insulating antenna bobbin which has the pattern of an element that resonates in a plurality of frequency bands, formed on the outer circumferential surface; and

a conductive parasitic conductor which is inserted into an accommodating hole formed substantially along the central axis of the antenna bobbin.

2. The multiple resonance antenna according to claim 1, wherein the lower part of the antenna bobbin is engaged with a conductive antenna holder, the antenna holder and the element are electrically connected, and an insulating cap part that covers the antenna bobbin is mounted on the upper part of the antenna holder.

3. The multiple resonance antenna according to claim 1, wherein the pattern of the element is formed so that this pattern is folded back, and short-circuiting parts that connect the folded-back portions of the pattern are formed.

4. A mobile phone antenna comprising:

a fixed antenna part which can be fastened to the housing of a mobile phone; and

a retractable antenna part which passes through the fixed antenna part, and is retractable with respect to the fixed antenna part;

wherein the fixed antenna part is constructed from an insulating antenna bobbin which has the pattern of an element that resonates in a plurality of frequency bands, formed on the outer circumferential surface, a conductive parasitic conductor which is inserted into a through-hole formed substantially along the central axis of the antenna bobbin, a conductive antenna holder with which the lower part of the antenna bobbin is engaged, and to which the element is electrically connected, and an insulating cap part which covers the antenna bobbin, and

the retractable antenna part is constructed from a whip part, a conductive stopper which is disposed on the lower end of the whip part and which is held inside an antenna through-hole formed substantially along the central axis of the fixed antenna part when the retractable antenna part is extended, and an insulative insulating part which is disposed on the tip end of the whip part, and which is positioned inside the antenna through-hole when the retractable antenna part is retracted.

5. The mobile phone antenna according to claim 4, wherein a conductive expanded-diameter part is disposed at an intermediate point on the whip part, and the expanded-diameter part is positioned inside a through-hole in the antenna bobbin when the whip part is extended.

6. The mobile phone antenna according to claim 4, wherein a conductive part is disposed, instead of the parasitic conductor, on a portion of the insulating part that is positioned inside the antenna through-hole in the retracted state.

7. The mobile phone antenna according to claim 5, wherein a conductive contact spring that contacts the inside of a through-hole in the parasitic conductor when the whip part is extended is installed instead of the expanded-diameter part.

8. The mobile phone antenna according to claim 4, wherein a conductive film is formed, instead of the parasitic conductor, on the inner circumferential surface of a through-hole in the antenna bobbin.