CN201699133U

CN201699133U - Antenna structure of wireless radio frequency identification system

Info

Publication number: CN201699133U
Application number: CN 201020157889
Authority: CN
Inventors: 张靖玮; 蔡健民
Original assignee: Auden Techno Corp
Current assignee: Auden Techno Corp
Priority date: 2010-04-14
Filing date: 2010-04-14
Publication date: 2011-01-05
Anticipated expiration: 2020-04-14

Abstract

An antenna structure of a wireless radio frequency identification system is mainly composed of a metal plate and a printed circuit board. The metal plate is a dipole antenna, and the printed circuit board is arranged between the metal plate and the printed circuit board. Two transformers are arranged on the printed circuit board to generate a balun area, respectively making the dipole antenna resonate at the vertical and horizontal poles; and the two transformers are respectively connected to a matching layout, and the two matching layouts are changed according to the operating frequency band of the wireless radio frequency identification system.

Description

The antenna structure of radio frequency identification system

Technical field

The utility model can reach same antenna structure and use under different operational frequency bands by the change of matching element about a kind of antenna structure of radio frequency identification system.

Background technology

Radio frequency identification system (Radio Frequency Identification, be abbreviated as RFID), the system that is formed by an inductor (Reader) and a RFID label (Tag) normally, the principle of its running is to utilize the inductor emitting radio wave, RFID label in the touch inducing scope, produce electric current by electromagnetic induction, the wafer running on the supply RFID label is also sent electromagnetic wave and is responded inductor.To drive the energy source difference, the RFID label can be divided into active and two kinds of passive types: the label of passive type itself does not have the device of battery, required electric current produces by the radio wave electromagnetic induction of inductor entirely, so only receiving the response inductor that signal that inductor sends just can be passive; And active label is built-in with battery, can initiatively transmit signal and read for inductor, and it is wide that signal transmits the also relative ratio passive type of scope.

The antenna structure of general radio frequency identification system is to adopt the dipole design, therefore a printed circuit board (PCB) need be set in antenna, and two transformers of layout are to produce a Ba Lun zone (Balun area) on it.Since be a dipole formula design, the antenna of perpendicular polarization and horizontal polarization can produce resonance at two different utmost points.

But, the present operational frequency bands of RFID, different and set according to each department, for example, be 902～928MHz in the operational frequency bands of the U.S., Europe then is 865～869MHz.Therefore, at the antenna structure of RFID, must design according to different areas, cause manufacturing cost to increase, unfavorable production remains to be improved.

Summary of the invention

Edge this, the purpose of this utility model has been to provide a kind of antenna structure of radio frequency identification system, the operational frequency bands that they can adaptive different regions, and simple in structure, easy operating can be saved cost thus, is beneficial to produce and use.

For achieving the above object, the utility model discloses a kind of antenna structure of radio frequency identification system, comprising:

One metallic plate forms a dipole antenna; And

One printed circuit board (PCB) is arranged at this metallic plate centre position, on it at least layout have and produce the Ba Lun zone and this dipole antenna is resonated in two transformers at vertical and horizontal the two poles of the earth;

It is characterized in that: two transformers of this of this printed circuit board (PCB) connect a coupling layout that changes according to the operational frequency bands of this radio frequency identification system respectively.

Wherein, the operational frequency bands of this radio frequency identification system is 902～928MHz, and the coupling layout of the transformer of this perpendicular polarization is a resistance, and the coupling layout of the transformer of this horizontal polarization comprises an electric capacity and an inductance.

Wherein, this resistance value is 0 Ω, and this capacitance is 1.3pF, and this inductance value is 1.5nH.

Wherein, the operational frequency bands of this radio frequency identification system is 865～869MHz, and the coupling layout of the transformer of this perpendicular polarization is one first inductance and a resistance, and the coupling layout of the transformer of this horizontal polarization comprises electric capacity and one second inductance.

Wherein, this first inductance value is 3.7nH, and this resistance value is 5.6 Ω, and this capacitance is 2.7pF, and this second inductance value is 3.3nH.

By said structure, the antenna structure of a kind of radio frequency identification system of the present utility model is level and vertical polarized antenna, its original frequency band width can be positioned at the RFID operational frequency bands of 902～928MHz U.S.; And, resonance frequency is changed over 865～869MHz operational frequency bands of Europe regulation by implementing matching element.By this, can that is to say that under the same antenna structure, as long as the printed circuit board (PCB) of different coupling layouts is installed, this greatly reduces with same antenna structure applications in different operational frequency bands on manufacturing cost.

Below, design feature of the present utility model will be described in detail according to the embodiment shown in the drawing and use effect.

Description of drawings

Fig. 1 represents front view of the present utility model,

Fig. 2 represents rear view of the present utility model,

Fig. 3 represents the zoomed-in view of the utility model printed circuit board (PCB),

On behalf of the utility model, Fig. 4 be used in the coupling layout circuit figure of U.S.'s predetermined operation frequency band,

Fig. 5 A and Fig. 5 B by the operational frequency bands that embodiment shown in Figure 4 is used in U.S. regulation tested horizontal polarization result,

Fig. 6 A and Fig. 6 B by the operational frequency bands that embodiment shown in Figure 4 is used in U.S. regulation tested perpendicular polarization result,

On behalf of the utility model, Fig. 7 be used in the coupling layout circuit figure of European predetermined operation frequency band,

Fig. 8 A and Fig. 8 B by the operational frequency bands that embodiment shown in Figure 7 is used in Europe regulation tested horizontal polarization result,

Fig. 9 A and Fig. 9 B by the operational frequency bands that embodiment shown in Figure 7 is used in Europe regulation tested perpendicular polarization result.

Embodiment

See also Figure 1 and Figure 2, the utility model provides a kind of antenna structure 1 of radio frequency identification system, and it mainly is made of a metallic plate 11 and a printed circuit board (PCB) 12.

Metallic plate 11 is designed to a dipole (dipole) antenna, and promptly the antenna of perpendicular polarization (verticallypolarized) and horizontal polarization (horizontally polarized) resonates to produce at two different utmost points.And printed circuit board (PCB) 12 is set at metallic plate 11 centre positions, and layout on it (layout) has two transformers (transformer) 121 and 122 to produce Ba Lun zone (Balun area), and dipole antenna is resonated in vertical and horizontal the two poles of the earth.

As shown in Figure 3, the utility model mainly connects a coupling layout (matching layout) 123 and 124 respectively at two

transformers

121 and 122 of printed circuit board (PCB) 12, and this two

coupling layout

123 and 124 operational frequency bands according to radio frequency identification system change.

For example, it is 902～928MHz that radio frequency identification system uses the operational frequency bands in U.S.'s regulation, then as shown in Figure 4, the coupling layout 123 of the transformer 121 of perpendicular polarization is a resistance R, and the coupling layout 124 of the transformer 122 of horizontal polarization comprises a capacitor C and an inductance L.Wherein resistance value is 0 Ω, and capacitance is 1.3pF, and inductance value is 1.5nH.

Referring to Fig. 5 A and Fig. 5 B, the operational frequency bands that is used in U.S. regulation by embodiment shown in Figure 4 tested horizontal polarization result, Fig. 6 A and Fig. 6 B then for test perpendicular polarization result.

Again for example, it is 865～869MHz that radio frequency identification system uses the operational frequency bands in the Europe regulation, then as shown in Figure 7, the coupling layout 123 of the transformer 121 of perpendicular polarization is one first inductance L 1 and a resistance R, and the coupling layout 124 of the transformer 122 of horizontal polarization comprises a capacitor C and one second inductance L 2.Wherein first inductance value is 3.7nH, and resistance value is 5.6 Ω, and capacitance is 2.7pF, and second inductance value is 3.3nH.

Referring to Fig. 8 A and Fig. 8 B, the operational frequency bands that is used in Europe regulation by embodiment shown in Figure 7 tested horizontal polarization result, Fig. 9 A and Fig. 9 B then for test perpendicular polarization result.

As from the foregoing, as long as the utility model is with the coupling of two on the printed circuit board (PCB) 12

layout

123 and 124, design according to the operational frequency bands of radio frequency identification system, can be with same antenna structure applications in different operational frequency bands, that is to say, under the same antenna structure, as long as the printed circuit board (PCB) of different coupling layouts is installed, this greatly reduces on manufacturing cost.

To sum up institute is old, and the utility model meets novelty of patent and progressive important document fully, files an application in the whence in accordance with the law.Noticeable, the coupling layout shown in the figure only is the utility model preferred embodiment, not as limit; In every case the simple and easy change of being made according to the utility model technological thought, still belong to protection range in.

Claims

1. An antenna structure for a radio frequency identification system, comprising:

a metal plate forming a dipole antenna; and

A printed circuit board, arranged in the middle of the metal plate, on which at least two transformers that generate a balun area and respectively make the dipole antenna resonate at vertical and horizontal poles are laid out;

It is characterized in that: the two transformers of the printed circuit board are respectively connected to a matching layout that changes according to the operating frequency band of the radio frequency identification system.

2. The antenna structure of the radio frequency identification system according to claim 1, wherein the operating frequency band of the radio frequency identification system is 902-928 MHz, and the matching layout of the vertically polarized transformer is a resistor, and the The matching layout of the horizontally polarized transformer includes a capacitor and an inductor.

3. The antenna structure of the radio frequency identification system according to claim 2, wherein the resistance value is 0Ω, the capacitance value is 1.3pF, and the inductance value is 1.5nH.

4. The antenna structure of the radio frequency identification system according to claim 1, wherein the operating frequency band of the radio frequency identification system is 865-869 MHz, and the matching layout of the vertically polarized transformer is a first inductor and a resistor, and the matching layout of the horizontally polarized transformer includes a capacitor and a second inductor.

5. The antenna structure of the radio frequency identification system according to claim 4, wherein the first inductance value is 3.7nH, the resistance value is 5.6Ω, the capacitance value is 2.7pF, and the second inductance value is 3.3nH. the