DUAL-BAND ANTENNA

• US 20100103050A1
• Filed: 01/30/2009
• Published: 04/29/2010
• Est. Priority Date: 05/22/2008
• Status: Active Grant

• Current Assignee: Harada Industry Company Limited
• Original Assignee: Nippon Antena Kabushiki Kaisha (Nippon Antenna Company Limited)
• Inventors: Shimizu, Hiroshi
• Granted Patent: US 8,089,410 B2
• Time in Patent Office: Days
• US Class Current: 343/700.MS
• CPC Class Codes: H01Q 1/32 Adaptation for use in or on road or rail vehicles
• 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 5/321 within a radiating element or between connected radiating elements
• CPC Class Codes: H01Q 5/364 Creating multiple current paths
• CPC Class Codes: H01Q 9/36 with top loading
• CPC Class Codes: H01Q 9/40 Element having extended radiating surface

Abstract

The present invention provides a dual-band antenna that can be operated at two frequencies without providing the choke coil. A first element operated in a high-frequency-side band is formed in a surface of a print board using a print pattern. A second element operated in a low-frequency-side band is formed in an upper portion of a rear surface of the print board so as not to overlap the first element. A power is fed to the first element from a power feeding point located at a lower end of the print board, and the power is fed to the second element through a throughhole made in a middle of the first element. The power is fed to the second element from the throughhole through a long and thin power feeding line, and the power feeding line exhibits a high impedance to a high frequency. A slit is formed in the first element corresponding to the power feeding line.

Claims

1. A dual-band antenna comprising:

a first element that is formed into a planar shape in one of surfaces of an insulating board from a lower end of the board toward an upper portion of the board;

a second element that is formed in an upper portion of the other surface of the board so as not to overlap the first element;

a gland that is disposed at the lower end of the board;

power feeding means for feeding power to the lower end of the first element; and

a throughhole that is made in an end portion of a power feeding line and connected to a middle of the first element, the power feeding line being led out from the second element formed in the other surface of the board,

wherein a slit is formed in a region of the first element, the region of the first element corresponding to the power feeding line.

2. The dual-band antenna according to claim 1, wherein a tapered portion is formed toward a lower end from at the middle of the first element.

3. The dual-band antenna according to claim 1, wherein both sides of the second element are folded downward, and the power feeding line is drawn from a substantial center of the second element.

4. The dual-band antenna according to claim 1, wherein the first element and the second element include print patterns formed on the board.