Antenna Construction, for Example for an RFID Transponder System

• US 20090096612A1
• Filed: 05/08/2006
• Published: 04/16/2009
• Est. Priority Date: 05/12/2005
• Status: Active Grant

• Current Assignee: Valtion Teknillinen Tutkimuskeskus
• Original Assignee: Valtion Teknillinen Tutkimuskeskus
• Inventors: Seppa, Heikki, Jaakkola, Kaarle
• Granted Patent: US 7,724,143 B2
• Time in Patent Office: Days
• US Class Current: 340/572.7
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• 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 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
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence

Abstract

The invention relates to an antenna construction for a double-ended antenna circuit 4. The antenna construction comprises a conductive ground place (6) on a first surface, a transmission line (3) on at least one second surface, connected to the ground plane (6) through a fold (1) in the edge of the antenna construction, so that the fold acts as a primary source of a magnetic field, an insulation layer (7) arranged between the first and the second surfaces, and an electronic component (4), in which there is a double-ended antenna connector, connected to the antenna construction. According to the invention, the electronic component (4) is attached to the second surface of the antenna construction and connected from the first antenna terminal to the transmission line (3) and from the second terminal to either a second transmission line (3) or the fold (1).

Claims

1. Antenna construction for a double-ended antenna circuit (4), which comprises

a conductive ground place (6) on a first surface,

a transmission line (3) on at least one second surface, the transmission line connected to the ground plane (6) through a fold (1) in the edge of the antenna construction, so that the fold acts as a primary source of a magnetic field,

an insulation layer (7) arranged between the first and the second surfaces, and

an electronic component (4), in which there is a double-terminal antenna connector, connected to the antenna construction,

characterized in that

the electronic component (4) is attached to the second surface of the antenna construction and connected from the first antenna terminal to the transmission line (3) and from the second terminal to either a second transmission line (3) or the fold (1).

2. Antenna construction according to claim 1, characterized in that the length of the transmission line (3) connected to the first antenna terminal of the component (4) is λ

*(2 n−

1)¼

, where n=1,2,3.

3. Antenna construction according to claim 1 or 2, characterized in that the length of the transmission line (3) connected to the second antenna terminal of the component (4) is λ

*n½

, where n=0, 1, 2, 3.

4. Antenna construction according to claim 3, characterized in that the second antenna terminal of the component (4) is connected to the fold (1), in which case n=0.

5. Antenna construction according to claim 3, characterized in that the second antenna terminal of the component (4) is connected to the transmission line (3), the length of which is λ

*(2n−

1)¼

.

6. Antenna construction according to any of the above claims, characterized in that the component (4) is a passive RFID circuit.

7. The use of the antenna construction according to any of the above claims as the antenna of an RFID circuit.