Patent Application
20120126016
1. Field of the Invention
The invention relates to a RFID electric tag, and more particularly, to a planar antenna having a function of RFID electric tag.
2. Description of Prior Art
RFID electric tags have been widely used in the logistics area. It may store data related to merchandise, credit card or access card on a RFID chip. When RFID reader reads the data, the action of merchandise payment, merchandise inventory management, credit card usage and identity identification, etc. can be finished.
A traditional method for manufacturing RFID electric tags comprises first preparing a plastic sheet, providing a reception and emission antenna on the plastic sheet, gluing a RFID chip on the plastic sheet and electrically connecting the pins and the antenna. When finishing the manufacture of the RFID electric tags, adhesives may be directly coated on a surface of plastic sheet having the antenna and RFID chip so that the RFID electric tags may be adhered to merchandise.
The traditional RFID electric tags have a deficiency of susceptible to ambient factors, such as usage in the water or liquid and high humid environment, easily causing interference and diffraction. Alternative, when providing traditional RFID electric tags on a surface of metal, it may cause high ratio of error of reading data.
It is a main object of the invention to improve the above deficiency of the traditional RFID electric tags by a combination of RFID chip and planar antenna. The larger the area of the grounding metal layer of the planar antenna is, the better reception the planar antenna is. Therefore, the planar antenna having a RFID electric tag can be used in the aspects of a metal surface and merchandise with a larger metal surface and liquid merchandise without interference when a RFID reader reads data.
The object described above is achieved by a planar antenna having a RFID electric tag of the invention. The planar antenna having a RFID electric tag comprises: a substrate made of ceramic material, the substrate having a front surface and a rear surface thereon; a radiating metal layer provided on the front surface of the substrate, the radiating metal layer having an area which is equal to or less than the area of the front surface of the substrate, the radiating metal layer having at least a first electrode on its one side; a grounding metal layer provided on the rear surface of the substrate, the grounding metal layer having an area which is equal to or less than the area of the rear surface of the substrate, the grounding metal layer having at least a second electrode on its one side which extends to the front surface of the substrate; a RFID chip provided on the front surface of the substrate, the RFID chip having a plurality of pins on its two sides, the pins electrically connecting to the first electrode and the second electrode.
A preferred embodiment of the present invention will be described with reference to the drawings.
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The substrate 1 is made of ceramic material to present a square or rectangular body, and has a front surface 11 and a rear surface 12 thereon.
The radiating metal layer 2 is provided on the front surface 11 of the substrate 1. The radiating metal layer 2 may be used for signal reception and emission. Also, the radiating metal layer 2 has an area which is equal to or less than the area of the front surface 11 of the substrate 1. The radiating metal layer 2 has at least a first electrode (microstrip) 21 on its one side.
The grounding metal layer 3 is provided on the rear surface 12 of the substrate 1 for grounding. The grounding metal layer 3 has an area which is equal to or less than the area of the rear surface 12 of the substrate 1. The grounding metal layer 3 has at least a second electrode 31 on its one side which extends to the front surface 11 of the substrate 1.
The RFID chip 4 may be made by a well-known art. The RFID chip 4 is provided on the front surface 11 of the substrate 1. The RFID chip 4 has a plurality of pins 41 on its two sides to electrically connect to the first electrode 21 and the second electrode 31. The RFID chip 4 may receive a signal radiated from an external RFID reader (not shown in the drawings) by the radiating metal layer 2, and transmitting the signal of RFID chip 4 to the RFID reader.
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The base 51 has a chamber 511 for receive the planar antenna 10 therein. The chamber 511 has a groove 512 around the edge for connecting the cover 53. When connecting to the cover 53, a sealing strip or glue coating can be provided in the groove 512 to have a waterproof effect. In addition, the base 51 has joint holes 513 on two sides of the chamber 511, corresponding to each other. The joint holes 513 can be used for fastening the base 51 to the metal object. Alternative, a double-sided tape can be provided on the rear surface of the base 51 to adhere on the object directly.
The gummed tape 52 is a double-sided tape or an adhesive which is used for adhering the planar antenna 10 within the chamber 511.
The cover 53 is inserted into the groove 512. The cover 53 has an outer surface 531 and an inner surface 532. The outer surface 531 has a vent 533 penetrating through the cover 53.
The adhesive tape 54 with waterproof property and vapor permeability is provided on the inner surface 532 of the cover 53 to seal the vent 533. The adhesive tape 54 can prevent the external moisture from entering the chamber 511, while exhausting the moisture within the chamber 511 to keep the chamber 511 dry.
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Although the present invention has been described with reference to the foregoing preferred embodiment, it will be understood that the invention is not limited to the details thereof Various equivalent variations and modifications can still occur to those skilled in this art in view of the teachings of the present invention. Thus, all such variations and equivalent modifications are also embraced within the scope of the invention as defined in the appended claims.
