Compact loop antenna for inductive read/write apparatus

• US 20070030207A1
• Filed: 07/31/2006
• Published: 02/08/2007
• Est. Priority Date: 02/02/2004
• Status: Active Grant

• Current Assignee: Fujitsu Frontech Limited (Fujitsu Limited)
• Original Assignee: Fujitsu Frontech Limited (Fujitsu Limited)
• Inventors: Sugimura, Yoshiyasu, Hashimoto, Shigeru, Ibi, Toshiaki
• Granted Patent: US 7,259,726 B2
• Time in Patent Office: Days
• US Class Current: 343/742
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• 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: H04B 5/48 Transceivers
• CPC Class Codes: H04B 5/77 for interrogation
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

In order to provide a compact loop antenna, for use in an inductive read/write apparatus, capable of extending a communication range even if the antenna area or power supply thereto is constrained, a compact loop antenna, for use in an inductive read/write apparatus, comprises two layers of loop antennas, each thereof comprising a printed circuit board 2 for featuring a loop pattern 1, a loop pattern 1 formed by an etching process on the printed circuit board 2, and a start terminal 3 and a end terminal 4 for supplying power for signal transmission and outputting a received signal and each thereof maintaining a predetermined distance from each other.

Claims

1. A loop antenna, for use in an inductive read/write apparatus, comprising:

two or more loop patterns, by maintaining a predetermined distance from one to another, each of which being formed by at least one turn of spiral, wherein;

interconnecting respective start points of all the layered loop patterns and interconnecting respective end points thereof, thereby connecting all the layered loop patterns in parallel.

2. The loop antenna, for use in an inductive read/write apparatus, according to claim 1, wherein:

placing two or more boards, each of which is formed with one said loop pattern, in layers being maintained in a predetermined distance from one another.

3. The loop antenna, for use in an inductive read/write apparatus, according to claim 1, wherein:

placing said loop patterns in layers on a single board with the aforementioned loop patterns being maintained in a predetermined distance from one another.

4. The loop antenna, for use in an inductive read/write apparatus, according to claims 1, 2 or 3, further comprising

an inter-start point connection changeover unit for connecting between respective start points of said layered loop pattern selectively, and

an inter-end point connection changeover unit for connecting between respective end points of said layered loop pattern selectively.

5. The loop antenna, for use in an inductive read/write apparatus, according to claim 4, wherein :

said inter-start point connection changeover unit and said inter-end point connection changeover unit respectively change over connections according to a communication range.