Multifrequency antenna

• US 20030137463A1
• Filed: 10/03/2002
• Published: 07/24/2003
• Est. Priority Date: 02/26/2001
• Status: Active Grant

• Current Assignee: Hiroshi Shimizu
• Original Assignee: Hiroshi Shimizu
• Inventors: Shimizu, Hiroshi
• Granted Patent: US 6,714,164 B2
• Time in Patent Office: Days
• US Class Current: 343/713
• CPC Class Codes: H01Q 1/241 used in mobile communications, e.g. GSM H01Q1/247, H01Q1/248 take precedence
• CPC Class Codes: H01Q 1/32 Adaptation for use in or on road or rail vehicles
• CPC Class Codes: H01Q 1/3275 mounted on a horizontal surface of the vehicle, e.g. on roof, hood, trunk
• 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 23/00 Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 5/321 within a radiating element or between connected radiating elements
• CPC Class Codes: H01Q 5/378 Combination of fed elements with parasitic elements
• CPC Class Codes: H01Q 5/49 with parasitic elements used for purposes other than for dual-band or multi-band, e.g. imbricated Yagi antennas
• CPC Class Codes: H01Q 5/50 Feeding or matching arrangements for broad-band or multi-band operation
• CPC Class Codes: H01Q 9/30 with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence

Abstract

An antenna is compactified whilst being able to operate across at least two different broad frequency bands. An antenna circuit board 7 on which an antenna pattern 7a and a passive element pattern 7b are formed is accommodated inside an antenna case. An antenna element is connected electrically to the upper end of the antenna pattern 7a. An antenna operating in the GSM and DCS frequency bands is constituted by a telephone element provided on the lower portion of the antenna element and the antenna pattern 7a and passive element pattern 7b formed on the antenna circuit board 7. Thereby, a compactified antenna is enabled to operate across two different broad frequency bands.

Claims

1. A multi-frequency antenna comprising:

an antenna circuit board, on which are formed an antenna pattern, and a passive element pattern in the proximity of said antenna pattern;

an antenna case section for accommodating said antenna circuit board; and

an antenna element, in which a choke coil is disposed between an upper element and a lower element, the lower end of said lower element being connected to the upper end of said antenna pattern formed on said antenna circuit board when said antenna element is installed on said antenna case section;

wherein antenna means comprising said lower element, said antenna pattern and said passive element pattern is able to operate in a first frequency band, and a second frequency band, which is approximately double the frequency of the first frequency band.

2. The multi-frequency antenna according to claim 1, wherein said first frequency band and said second frequency band are mobile radio bands.

3. The multi-frequency antenna according to claim 1, wherein the whole of said antenna including said upper element and said choke coil is able to operate in a third frequency band, which is lower than said first frequency band.

4. The multi-frequency antenna according to claim 1, wherein frequency dividing means for dividing said first frequency band and said second frequency band from said third frequency band is incorporated into a circuit board accommodated inside said antenna case section.

5. The multi-frequency antenna according to claim 4, wherein said frequency dividing means includes a matching circuit for said first frequency band and said second frequency band.