Antenna and RFID tag

Abstract
An antenna for an RFID tag includes each power feeding parts 11 that is formed of a conductor, meandering parts 13a and 13b that are formed of conductors shaped as a pair of meandering lines, connected to the power feeding parts 11, and extend from the power feeding parts 11 toward both ends of the power feeding parts 11, respectively, a pair of radiating parts 14a and 14b that are formed of conductors and connected to outer ends of the pair of meandering parts 13a and 13b, respectively. The meandering parts 13a and 13b include a plurality of sides arranged in a longitudinal direction where the meandering parts 13a and 13b extend. Further, the lengths of portions, where the ends of the radiating parts 14a and 14b facing the meandering parts 13a and 13b face the sides closest to the radiating parts 14a and 14b among the plurality of sides of the meandering parts 13a and 13b in a direction orthogonal to the longitudinal direction, are smaller than the widths of the widest portions of the radiating parts.
Description

BRIEF DESCRIPTION OF THE DRAWINGS


FIG. 1A is a plan view of an RFID tag according to a first embodiment of the invention.



FIG. 1B is a bottom view of the RFID tag according to the first embodiment of the invention.



FIG. 1C is a front view of the RFID tag according to the first embodiment of the invention.



FIG. 1D is a rear view of the RFID tag according to the first embodiment of the invention.



FIG. 1E is a right side view of the RFID tag according to the first embodiment of the invention.



FIG. 1F is an enlarged view of the main parts of the RFID tag according to the first embodiment of the invention.



FIG. 1G is an enlarged view of the main parts of the RFID tag according to the first embodiment of the invention.



FIG. 2 is a plan view of a sample antenna for a simulation.



FIG. 3 is a plan view of a sample antenna for the simulation.



FIG. 4 is a view showing results of the simulation.



FIG. 5 is a view showing a relationship between the shape and the band of the antenna.



FIG. 6 is a plan view of an antenna according to a second embodiment of the invention.



FIG. 7 is a plan view of an antenna according to a third embodiment of the invention.



FIG. 8 is a view showing results of a simulation.



FIG. 9 is a view showing a relationship between the shape and the band of the antenna.


Claims
  • 1. An antenna for an RFID (Radio Frequency Identification) tag, comprising: a power feeding part formed of conductor;meandering parts that are connected to the power feeding part and extend from the power feeding part toward both ends of the power feeding part, respectively, the meandering parts being formed of conductors shaped as a pair of meandering lines; anda pair of radiating parts that are formed of conductors and connected to outer ends of the pair of meandering parts, respectively,wherein the meandering parts include a plurality of sides arranged in a longitudinal direction where the meandering parts extend, andthe length of portions, where ends of the radiating parts facing the meandering parts face the sides closest to the radiating parts among the plurality of sides of the meandering parts in a direction orthogonal to the longitudinal direction, are smaller than the widths of the widest portions of the radiating parts.
  • 2. The antenna according to claim 1, wherein the widths of the ends of the radiating parts facing the meandering parts are smaller than the widths of the widest portions of the radiating parts, andthe lengths of the sides closest to the radiating parts among the plurality of sides of the meandering parts in the direction orthogonal to the longitudinal direction are smaller than the widths of the ends of the radiating parts facing the meandering parts.
  • 3. The antenna according to claim 1, wherein the widths of the portions of the radiating parts facing the meandering parts decrease as coming close to the meandering parts.
  • 4. The antenna according to claim 1, wherein the lengths of two or more sides, facing the radiating parts, among the plurality of sides of the meandering parts in the direction orthogonal to the longitudinal direction decrease as coming close to the radiating parts.
  • 5. The antenna according to claim 1, further comprising: a matching circuit that is connected to the power feeding part.
  • 6. The antenna according to claim 1, wherein the plurality of sides extend in the direction orthogonal to the longitudinal direction.
  • 7. The antenna according to claim 1, wherein the antenna is an antenna for UHF band, and the antenna has a size equal to or smaller than a size of 25×100 mm.
  • 8. An RFID tag comprising: the antenna according to claim 1;an integrated circuit that is connected to the power feeding part of the antenna; anda dielectric substrate on which the antenna is disposed.
Priority Claims (1)
Number Date Country Kind
P2006-047867 Feb 2006 JP national