ANTENNA CIRCUIT AND TRANSPONDER

• US 20090201116A1
• Filed: 03/05/2007
• Published: 08/13/2009
• Est. Priority Date: 05/31/2006
• Status: Active Grant

• Current Assignee: Dexerials Corporation
• Original Assignee: Sony Chemical & Information Device Corporation (Sony Group Corp.)
• Inventors: Orihara, Katsuhisa
• Granted Patent: US 8,059,062 B2
• Time in Patent Office: Days
• US Class Current: 336/200
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• 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

Abstract

A transponder is provided capable of having desired characteristics by a method for forming a resonance circuit, despite the fact that its cost is low and its structure is simple. An antenna circuit is provided in the transponder and comprises an antenna conductor having a predetermined conductor pattern formed on the front surface of a substrate and a sheet metal disposed on the rear surface of the substrate. A part of the sheet metal is provided with a slit so formed that its start end and terminal end are opened to the area at which the sheet metal does not exist.

Claims

1-8. -8. (canceled)

9. :

An antenna circuit provided in a transponder that stores various data readable and/or writable and has a communication function, the antenna circuit having at least an antenna coil formed on the surface of the predetermined substrate, the antenna circuit comprising;

an antenna conductor having a predetermined conductor pattern composing the antenna coil formed on the front surface of the substrate;

a sheet metal disposed on the rear surface area of the substrate opposed to the front surface area of the substrate forming the antenna conductor on the rear surface of the substrate;

a resonant circuit formed by floating capacitance produced by the sheet metal and the antenna conductor; and

a slit provided in a part of the sheet metal having a start end and a terminal end opened to the area at which the sheet metal does not exist.

10. :

The antenna circuit according to claim 9, wherein the sheet metal has a loop configuration in which the central part is cut out so as to be disposed in the rear surface area of the substrate opposed to the front surface area of the substrate at which the spiral antenna conductor is formed, and wherein the slit is provided to cut off a part of the loop shape.

11. :

The antenna circuit according to claim 10, comprising another sheet metal disposed on an inner peripheral part of the loop-shaped sheet metal with a minute gap to be isolated electrically with the sheet metal.

12. :

The antenna circuit according to claim 11, wherein the sheet metal is provided with a plurality of the slits.

13. :

The antenna circuit according to claim 9, wherein the slit is provided to divide the sheet metal into plural number.

14. :

The antenna circuit according to claim 9, wherein the substrate is composed of a double-sided printed circuit board of which front and rear surfaces are provided with the predetermined electric conductor foil, wherein the antenna conductor is formed with electric conductor foil provided on the front surface of the substrate, and wherein the sheet metal is formed with electric conductor foil provided on the rear surface of the substrate.

10-1. :

The antenna circuit according to claim 9, wherein the sheet metal is provided with a plurality of the slits.

11-2. :

The antenna circuit according to claim 10, wherein the sheet metal is provided with a plurality of the slits.

15. :

A transponder that stores various data readable and/or writable and has a communication function, comprising;

an antenna circuit having at least an antenna coil on the surface of the predetermined substrate, the antenna circuit comprising;

an antenna conductor having a predetermined conductor pattern composing the antenna coil formed on the front surface of the substrate;

a sheet metal disposed on the rear surface area of the substrate opposed to the front surface area of the substrate forming the antenna conductor on the rear surface of the substrate;

a resonant circuit by floating capacitance produced by the sheet metal and the antenna conductor; and

a slit provided in a part of the sheet metal, wherein the slit has a start end and a terminal end opened to the area at which the sheet metal does not exist; and

an IC chip mounted on the antenna circuit.