TW201405945A - Dual polarized RFID antenna - Google Patents

Abstract

The invention relates to a dual polarized RFID antenna comprising a base, wherein the surface of the base is disposed with a radiation metal frame, with a section of the radiation metal frame electrically connected to a chip. The left and right sides of the radiation metal frame are respectively disposed with a coupling metal surface. Each coupling metal surface is respectively disposed with a level radiation metal wire and a vertical metal wire. A metal section is connected between two coupling metal surfaces. Therefore, after each level radiation metal wire or each vertical radiation metal wire generates induced current, the wire will be coupled to the radiation metal frame through the coupling metal surface so as to provide the usage of the chip while in use. Accordingly, the dual polarized RFID antenna of the invention has advantages of better reading distances, covering whole UHF frequency band, better impedance match.

Description

Dual polarized RFID antenna

The present invention relates to an antenna, and more particularly to a dual polarized RFID antenna.

RFID is the abbreviation of "Radio Frequency Identification". Chinese can be called "Radio Frequency Identification". This is a non-contact automatic identification system that uses radio waves to transmit identification data. The non-contact automatic identification system includes: Tag, a reader (Reader) and a computer information system.
The RFID tag basically consists of an antenna that transmits electromagnetic signals and a silicon chip that can store data, and then is packaged in glass or plastic components. The RFID tag in the sensing range generates an induced current through the antenna and the electromagnetic wave, and after supplying the chip on the RFID tag, the electromagnetic wave is transmitted through the antenna to the reader. Different from the source of driving energy, RFID tags can be divided into active and passive: passive RFID tags do not have batteries themselves, and the required current depends on receiving radio waves from the reader to generate induced current, so only when receiving The signal sent to the reader will passively respond to the reader; and the active RFID tag has a battery inside, which can actively transmit signals for reading by the reader, and the signal transmission range is relatively more passive. The RFID tag is wide.
However, RFID tags still have shortcomings in the UHF band. For example, the read distance is insufficient, the entire UHF band cannot be covered, and impedance matching still needs to be strengthened. Accordingly, the inventors believe that such an RFID tag needs to be improved.

In order to solve the deficiencies described in the prior art, the inventors propose a dual-polarized RFID antenna comprising:
A substrate.
A radiant metal frame:
One segment of the radiant metal frame is electrically connected to a wafer.
A first antenna:
The first antenna is disposed on the surface of the substrate, and the first antenna includes a first horizontal radiating metal line and a first vertical radiating metal line and a first coupling metal surface, wherein the first coupling metal surfaces are respectively connected The first horizontal radiating metal line and the first vertical radiating metal line, and the first coupling metal surface is located on a left side of the radiating metal frame.
A second antenna:
The second antenna is disposed on the surface of the substrate, and the second antenna includes a second horizontal radiant metal line and a second vertical radiant metal line and a second coupled metal surface. The second horizontal radiating metal line and the second vertical radiating metal line are connected, and the second coupling metal surface is located on the right side of the radiating metal frame.
a metal segment:
The two ends of the metal segment are respectively connected to the first coupling metal surface and the second coupling metal surface.
With the above configuration, the dual-polarized RFID antenna of the present invention generates an induced current by each radiating metal wire, and then uses the coupling metal faces to couple the induced current to the radiating metal frame to make the double The polarized RFID antenna can cover the entire UHF frequency band and has a better reading distance, and utilizes the radiating metal frame and the metal segment to make the dual polarized RFID antenna have better impedance matching.

The construction, features and embodiments of the present invention are illustrated by the accompanying drawings, which will be further understood by the review.
Referring to the first figure, the present invention relates to a dual-polarized RFID antenna, comprising:
A substrate (1):
The substrate (1) may be selected from a glass fiber board, a ceramic substrate, or the like, and is preferably an FR4 fiberglass board, and the substrate (1) preferably has a thickness of 0.2 (1±5%) mm, and the substrate (1) The area is preferably 66*33 (1±5%) mm ² , and the loss tangent of the substrate (1) is preferably 0.0245 (1±5%).
A radiating metal frame (2):
The radiant metal frame (2) is preferably a rectangular shape, and a portion of the radiant metal frame (2) is electrically connected to a wafer (3). In the present invention, the radiant metal frame (3) is preferably disposed on the radiant metal frame (2). One of the long sides is electrically connected to the radiating metal frame (2). The radiation metal frame (2) can improve the impedance matching of the dual-polarized RFID antenna (A), and the area of the radiation metal frame (2) is preferably 12.8*5.1 (1±5%) mm ² to make the double The polarized RFID antenna (A) has better impedance matching.
A first antenna 埠 (4):
The first antenna 埠 (4) is disposed on a surface of the substrate (1), the first antenna 埠 (4) includes a first horizontal radiant metal line (41) and a first vertical radiant metal line (42) And a first coupling metal surface (43), the first coupling metal surface (43) is respectively connected to the first horizontal radiation metal line (41) and the first vertical radiation metal line (42), and the first coupling metal The face (43) is located on the left side of the radiant metal frame (2). The first vertical radiating metal wire (42) and the first horizontal radiating metal wire (41) are preferably respectively provided with at least one bent portion (411, 421), thereby reducing the dual polarized RFID (A) The overall area. The vertical radiant metal wire and the horizontal radiant metal wire referred to in this specification are: the shape of the radiant metal wire, so that the signal from the vertical direction has a better receiving effect, which is called a vertical radiant metal wire; The shape of the radiating metal wire is such that the signal from the horizontal direction has a better receiving effect, which is called a horizontal radiating metal wire.
A second antenna 埠 (5):
The second antenna 埠 (5) is disposed on a surface of the substrate (1), and the second antenna 埠 (5) includes a second horizontal radiant metal line (51) and a second vertical radiant metal line (52) and a second coupling metal surface (53) connecting the second horizontal radiation metal line (51) and the second vertical radiation metal line (52), respectively, and the second coupling metal surface (53) is located on the right side of the radiant metal frame (2). The second horizontal radiating metal wire (51) and the second vertical radiating metal wire (52) are preferably respectively provided with a bent portion (511, 512), thereby reducing the overall size of the dual polarized RFID antenna (A). Area.
Moreover, the dual-polarized RFID antenna (A) can change its resonant frequency by adjusting the length of each radiating metal wire, and the first horizontal radiating metal wire (41) and the second horizontal radiating metal wire (51) Preferably, the length is 321 (1±5%) mm, and the length of the first vertical radiating metal wire (42) and the second vertical radiating metal wire (52) is preferably 412 (1±5%). Mm so that the dual polarized RFID antenna (A) can cover the operating band of the entire UHF.
a metal segment (6):
The two ends of the metal segment (6) are respectively connected to the first coupling metal surface (43) and the second coupling metal surface (53), and the dual polarization RFID can be adjusted by adjusting the length of the metal segment (6). The impedance of the antenna (A) is matched, and the length of the metal segment (6) is preferably 6.5 (1 ± 5%) mm.
Therefore, with the above configuration, the dual-polarized RFID antenna (A) of the present invention transmits or receives a signal by each radiating metal line, and thus, for example, when the first horizontal radiating metal line (41) receives a signal, When the current is induced, the induced current is coupled to the radiating metal frame (2) through the first coupling metal surface (43), so that the radiating metal frame (2) generates an induced current for use by the wafer (3), and The dual-polarized RFID antenna (A) has a better radiation pattern using the horizontal radiating metal wires (41, 51) and the respective vertical radiating metal wires (42, 52). Therefore, the dual-polarized RFID antenna (A) of the present invention has a bandwidth of about 139 (1 ± 5%) MHz, and covers the entire UHF band, and the reading distance is about 5 meters. In addition, the radiating metal frame (2) and the metal segment (6) enable the dual polarized RFID antenna (A) to have better impedance matching.
Referring to the second figure, the figure is a graph showing the results of the return loss of the dual-polarized RFID antenna (A), wherein the vertical axis represents the return loss (dB) and the horizontal axis represents the operating frequency (MHz). As can be seen from the figure, the dual-polarized RFID antenna (A) can cover the entire UHF band (834 MHz to 973 MHz).
Referring to the third figure, the figure is a schematic diagram of the result of measuring the read range of the dual-polarized RFID antenna (A). It can be seen from the figure that the double-polarized RFID antenna (A) has the longest reading distance. It can be up to 5 meters.
In summary, the present invention is indeed in line with industrial utilization, and is not found in publications or publicly used before application, nor is it known to the public, and has non-obvious knowledge, conforms to patentable requirements, and patents are filed according to law. .
However, the above description is a preferred embodiment of the invention in the industry, and all the equivalent changes made according to the scope of the patent application of the present invention belong to the scope of the claim.

(A). . . Dual polarized RFID antenna

(1). . . Substrate

(2). . . Radiation metal frame

(3). . . Wafer

(4). . . First antenna

(41). . . First horizontal radiant metal line

(411). . . Bending section

(42). . . First vertical radiant metal line

(421). . . Bending section

(43). . . First coupling metal surface

(5). . . Second antenna

(51). . . Second horizontal radiant metal wire

(511). . . Bending section

(52). . . Second vertical radiant metal line

(521). . . Bending section

(53). . . Second coupling metal surface

(6). . . Metal segment

The first picture is the appearance of the creation. The second picture is the result of measuring the return loss of the dual-polarized RFID antenna. The third picture is the result of measuring the read range of the dual-polarized RFID antenna.

(A). . . Dual polarized RFID antenna

(1). . . Substrate

(2). . . Radiation metal frame

(3). . . Wafer

(4). . . First antenna

(41). . . First horizontal radiant metal line

(411). . . Bending section

(42). . . First vertical radiant metal line

(421). . . Bending section

(43). . . First coupling metal surface

(5). . . Second antenna

(51). . . Second horizontal radiant metal wire

(511). . . Bending section

(52). . . Second vertical radiant metal line

(521). . . Bending section

(53). . . Second coupling metal surface

(6). . . Metal segment

Claims (5)

A dual polarized RFID antenna comprising:
a substrate;
a radiating metal frame: a section electrically connected to a wafer;
a first antenna 埠 is disposed on the surface of the substrate, the first antenna 埠 includes a first horizontal radiant metal line and a first vertical radiant metal line and a first coupling metal surface, and the first coupling metal surface is respectively connected The first horizontal radiating metal line and the first vertical radiating metal line, and the first coupling metal surface is located on a left side of the radiating metal frame;
a second antenna 埠 is disposed on the surface of the substrate, the second antenna 埠 includes a second horizontal radiant metal line and a second vertical radiant metal line and a second coupling metal surface, and the second coupling metal surface respectively Connecting the second horizontal radiating metal line and the second vertical radiating metal line, and the second coupling metal surface is located at a right side of the radiating metal frame;
a metal segment: the two ends are respectively connected to the first coupling metal surface and the second coupling metal surface. The dual-polarized RFID antenna of claim 1, wherein the radiant metal frame is a rectangle and has an area of 12.8*5.1 (1±5%) mm ² . The dual-polarized RFID antenna according to claim 1, wherein the first horizontal radiation metal wire and the second horizontal radiation metal wire have a total length of 321 (1±5%) mm, and the first vertical radiation The length of the metal wire and the second vertical radiant metal wire is 412 (1 ± 5%) mm in total. The dual-polarized RFID antenna according to claim 1, wherein the substrate is an FR4 fiberglass board having a thickness of 0.2 (1±5%) mm and an area of 66*33 (1±5%) mm ^{2 .} The loss tangent is 0.0245 (1±5%). The dual-polarized RFID antenna of claim 1, wherein the length of the metal segment is 6.5 (1 ± 5%) mm.