Miniaturized radio-frequency identification tag and microstrip patch antenna thereof

• US 8,678,295 B2
• Filed: 04/02/2010
• Issued: 03/25/2014
• Est. Priority Date: 01/20/2010
• Status: Active Grant

• Current Assignee: Xerafy Singapore Pte. Ltd.
• Original Assignee: Shanghai Yaochuan Information Technology Co., Ltd., Xerafy
• Inventors: Liu, Zhijia
• Primary Examiner(s): Le, Thien M
• Assistant Examiner(s): Brown, Claude J
• Application Number:
  US13/574,360
• Publication Number:
  US 20130043316A1
• Time in Patent Office: 1,453 Days
• Field of Search: 235/492, 340/572.7, 340/572.8, 343/700, 343/850, 343/853, 737/61, 738/49
• US Class Current: 235/492
• 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 9/0442 with particular tuning means

Abstract

A miniaturized Radio Frequency Identification (RFID) tag and a microstrip patch antenna thereof are provided. The miniaturized RFID tag includes: a chip, substrate and a microstrip patch antenna. The microstrip patch antenna is attached to a surface of the substrate and includes a power supply part and a radiation part connected with each other. The power supply part is connected with the chip through a microstrip line. Two sides of the radiation part are provided with at least one slit which has the length of one-half wavelength and enables the tag product to be used normally within a range of shorter than one-half normal wavelength. A maximum point and a minimum point are generated in the radiation part simultaneously, so the tag can be used normally without influencing the performance, even when the tag is in contact with any metal surface. The tag can be miniaturized at the same time.

Claims

1. A microstrip patch antenna applied in a miniaturized radio frequency identification tag (RFIT), comprising:

a radiation part comprising a first portion and a second portion with at least one slit between the first and the second portions;

a power supply part formed at an edge of the first portion away from the second portion such that the at least one slit is positioned between the power supply part and the second portion of the radiation part, said at least one slit having at least one continuously curved edge.

2. The microstrip patch antenna applied in the miniaturized RFIT according to claim 1, wherein the at least one slit is circular, oval or polygonal.

3. The microstrip patch antenna applied in the miniaturized RFIT according to claim 1, wherein the radiation part is circular, oval or polygonal.

4. The microstrip patch antenna applied in the miniaturized RFIT according to claim 1, wherein the radiation part and the power supply part are made of silver.

5. The microstrip patch antenna applied in the miniaturized RFIT according to claim 1, wherein a size of the at least one slit is adjustable.

6. The microstrip patch antenna applied in the miniaturized RFIT according to claim 1, wherein the power supply part is directly coupled to the radiation part such that the power supply part is formed from a planar structure having the radiation part and the power supply part.

7. A miniaturized radio frequency identification tag (RFIT), comprising:

a chip, a substrate and a microstrip patch antenna, wherein the microstrip patch antenna is attached to a surface of the substrate;

the microstrip patch antenna comprises a power supply part formed at an end of a radiation part, the power supply part; and

the power supply part is connected with the chip through a microstrip line protruding at least partially beyond the end of the radiation part, said chip being outside the radiation part on a side surface of the substrate perpendicular to a surface of the substrate having the microstrip patch antenna.

8. The miniaturized RFIT according to claim 7, wherein around the chip, a protective coating is provided according to a height of the chip.

9. The miniaturized RFIT according to claim 8, wherein the protective coating is ceramic or rubber.

10. The miniaturized RFIT according to claim 7, wherein the substrate is ceramic.

11. The miniaturized RFIT according to claim 7, wherein the microstrip patch antenna further comprises a ground with a connection part, the power supply part and the radiation part are placed on a surface opposite to the ground, and the power supply part and the connection part connect to the chip on the same surface as the power supply part, the same surface as the ground, or on the side surface where the power supply part is connected to the ground via the connection part.

12. The miniaturized RFIT according to claim 7, wherein the microstrip patch antenna is made of silver.

13. The miniaturized RFIT according to claim 7, wherein there is a space between two sides of the power supply part and the radiation part.

14. The miniaturized RFIT according to claim 7, wherein the radiation part is circular, oval or polygonal.

15. The miniaturized RFIT according to claim 7, wherein two sides of the radiation part are provided with at least one slit between the end having the power supply part and another end of the radiation part.

16. The miniaturized RFIT according to claim 15, wherein the slit is circular, oval or polygonal.

17. The miniaturized RFIT according to claim 16, wherein a size of the slit is adjustable.

18. The miniaturized RFIT according to claim 7, wherein the microstrip line is in a bent configuration to connect the power supply part to the chip.

19. The production method of claim 18 further comprising:

providing a protective coating according to a height of the chip, around the chip.

20. A production method for a microstrip patch antenna, comprising:

providing a chip, a substrate and a microstrip patch antenna;

attaching the microstrip patch antenna to a surface of the substrate; and

connecting the power supply part is connected with the chip through a microstrip line protruding at least partially beyond the end of the radiation part, said chip being outside the radiation part on a side surface of the substrate perpendicular to a surface of the substrate having the microstrip patch antenna.