CN202333115U - Microstrip patch type radio frequency identification (RFID) label antenna - Google Patents

Abstract

The utility model relates to a microstrip patch type radio frequency identification (RFID) label antenna. The RFID label antenna (9) is provided with a radiation plate (1), a substrate (2) and a substrate bottom plate (3) and is characterized in that a first opening annular groove (5) and a second opening annular groove (7) are formed in the substrate bottom plate (3), the resonance frequency of the RFID label antenna (9) is reduced through the coupling of the first opening annular groove (5) and the second opening annular groove (7), and the reading distance of the RFID label antenna (9) is improved. The utility model provides the miniature low-loss RFID label antenna (9) capable of realizing the remote-distance reading, meanwhile, the RFID label antenna (9) provided by the utility model has better broadband matching performance, and the broadband frequency higher than that in the prior art is formed.

Description

Microband paste formula RFID label antenna

Technical field

The present invention relates to a kind of RFID label antenna, especially relate to a kind of microband paste formula RFID label antenna.

Background technology

RFID (Radio Frequency Identification)---REID; It is a kind of non-contact automatic identification technology that utilizes radio communication to realize; It comprises electronic tag (tag), two major parts compositions of read write line (reader); Label and read write line with coding carry out contactless transfer of data through antenna, to accomplish the automatic identifying of certain distance.Present radio-frequency recognition system is divided according to the frequency range of using, can be divided into low frequency system (30～300KHz), medium-high frequency system (3-30MHz) and hyperfrequency and microwave system (300MHz-3GHz or greater than 33GHz).As fast, in real time, accurately gathering and the new and high technology of process information and the basis of message mark vertebraization; By universally acknowledged be one of big important technologies in this century ten; Along with demands of applications such as the clear gradually and logistics of uhf band Chinese Industrial Standards (CIS), intelligent transportation, digital scenic spots, the shared market share can be increasing in the RFID industry for uhf band RFID product.RFID label antenna and reading and writing device antenna are being brought into play important effect as the important tool of communicating by letter in recognition system.For the information on quick reading tag on the long operating distance; The system of high band just receives much concern; And the RFID label antenna is a part the most variable in the rfid system; And its design is faced with miniaturization, and conformalization, low cost, low-loss actual requirement are so optimal design RFID label antenna occupies critical role in whole rfid system.

It is still not the same in its high-frequency range that each system uses the frequency bandwidth of RFID label antenna at present; For example the frequency range of 866～868MHz is adopted in Europe; The U.S. then adopts 902～928MHz frequency range; When switching between the different frequency bands width of RFID label antenna in above-mentioned area, existing RFID label antenna is owing to bandwidth constraints, and the area that also is difficult in the different frequency bands width is identified.And; Because when existing RFID label antenna is lower than 910MHz at dielectric thickness less than 1mm and resonance frequency; It is obviously not good to cause reading distance; For obtaining good identification effect, just must increase the thickness and the length and width size of existing RFID label antenna, bring RFID label antenna overall dimension to increase and cost increase thus.

Therefore, a kind of novel small-sized RFID label antenna that can discern at a distance with compatibility function becomes the direction of production development in the industry.

Summary of the invention

The object of the invention is to provide a kind of microband paste formula RFID label antenna; The present invention be directed to the RFID label antenna that works in metal surface and nonmetallic surface and design, and, when it is used at nonmetallic surface; Show good especially; The present invention is based on the RFID label antenna of ultra-thin medium 1mm and following time design, RFID label antenna of the present invention, the characteristics that have miniaturization, low-loss and can discern at a distance.

The present invention provides a kind of RFID label antenna; Comprise radiant panel, substrate and substrate base plate; It is characterized in that: be formed with the first open annular groove and the second open annular groove on the described substrate base plate; Through the coupling of the said first open annular groove and the second open annular groove, reduce the resonance frequency of RFID label antenna, improve the distance that reads of RFID label antenna.

RFID label antenna of the present invention is owing to increased open annular groove structure on the substrate base plate; The coupling of open annular groove is to reduce the resonance frequency of RFID label antenna; But RFID label antenna of the present invention has between higher bandwidth cog region; Bandwidth during than the imperforation cannelure has increased nearly 3 times, and the reading/writing distance when RFID label antenna of the present invention is than the imperforation cannelure simultaneously improves more than at least 1 times.

Description of drawings

Fig. 1 is the structure chart of RFID label antenna of the present invention;

Fig. 2 is the substrate base plate plane figure of RFID label antenna of the present invention.

Embodiment

Below in conjunction with accompanying drawing, practical implementation process of the present invention is described in detail.

Referring to Fig. 1 and Fig. 2, microband paste formula RFID label antenna 9 of the present invention has substrate 2 and is attached to the radiant panel 1 of upper surface of base plate respectively and the substrate base plate 3 of lower surface, and substrate 2 both sides have short circuit face 4.

Have coupling between the first open annular groove 5 and the second open annular groove, 7, the first open annular grooves 5 and the second open annular groove 7 on the substrate base plate 3 of the present invention,, improve the distance that reads of RFID label antenna to reduce the resonance frequency of RFID label antenna 9.

As preferred implementation of the present invention, the first open annular groove 5 and the second open annular groove 7 are square, and the top of the first open annular groove 5 has first opening, 6, the second open annular grooves, 7 belows and has second opening 8.The second open annular groove 7 is positioned at the first open annular groove, 5 inside and is that the center coincides and the setting of opening direction reverse.And the center of the first open annular groove 5 and the second open annular groove 7 and the center of RFID label antenna 9 coincide, and constitute the substrate base plate that has open annular groove structure of the present invention thus.

Beneficial effect of the present invention is specifically referring to table 1 data.

Table 1:

Table 1 is depicted as when RFID label antenna radiating element is measure-alike, relatively has on the substrate base plate 2, the contrast of the relevant parameter under two kinds of situation of imperforation cannelure.

According to formula (1):

$\mathrm{\λ}=\frac{C}{f\sqrt{{\mathrm{\ϵ}}_r}},$ Formula (1)

C in the formula (1) is the light velocity, ε _rBe relative dielectric constant, f is a frequency, and λ is a wavelength.Can find out by this formula; Parameter frequency f and wavelength X are inversely proportional to; And these two parameters and RFID label antenna radiating element size are related, and according to RFID label antenna design principle, RFID label antenna size need satisfy the relation of 1/4 wavelength or 1/2 wavelength; The λ wavelength is also followed and is become big when the f frequency reduces, and therefore the RFID label antenna size of design also can increase thereupon.The RFID label antenna resonance frequency of imperforation cannelure is 966MHz in the table 1; And of the present invention the resonance frequency of the RFID label antenna 9 of open annular groove is arranged is 910MHz; Under the measure-alike situation of RFID label antenna radiating element, RFID label antenna 9 of the present invention has lower resonance frequency, if when the antenna resonant frequency of imperforation cannelure downgraded 910MHz; RFID label antenna size can increase, will be greater than the size of RFID label antenna 9 of the present invention.In like manner, under the situation of identical resonance frequency, the present invention has the RFID label antenna 9 of open annular groove 5,7 can be littler than the RFID label antenna size that does not have the open annular groove.

Because of various countries use the RFID frequency inconsistent, be 866-868MHz like Europe, the U.S. is 902-928MHz; Under the identical radiating element size situation, the chip port reflection coefficient of various RFID label antennas also is not quite similar, and the impedance matching property of RFID label antenna of the RFID label antenna 9 relative imperforation cannelures of open annular groove is arranged in this patent for explanation; With this area used always-the 10db bandwidth is as reflection coefficient standard relatively; See shown in table 1 data that the RFID label antenna of imperforation cannelure has only 37MHz, be difficult to satisfy simultaneously the frequency requirement in above-mentioned two areas; Comparatively speaking; The bandwidth that the present invention is provided with the RFID label antenna 9 of open annular groove 5,7 rises to 100MHz, satisfies the 866-868MHz in Europe in the time of can be good, the 952-954MHz of the 902-928MHz of the U.S. and Japan.

Reading of RFID label antenna confirms it generally is according to formula (2) apart from r:

$r_{\mathrm{Max}}=\sqrt{\frac{\mathrm{EIRP}\·G_{\mathrm{Tag}}\·{\mathrm{\λ}}^2}{{\left(4\mathrm{\π}\right)}^2\·P_{\mathrm{Min}}}\·\mathrm{\η}},$ Formula (2)

R wherein _MaxBe maximum read distance, EIRP is an equivalent isotropically radiated power, G _TagBe the gain of RFID label antenna, λ is an electromagnetic wavelength in the vacuum, and η is a fissipation factor, P _MinSensitivity for label chip.Can know that by formula (2) it is far away more when the label gain is big more, to read distance.The RFID label antenna gain G of imperforation cannelure is-3.78db in the table 1, and the present invention has the gain G of the RFID label antenna 9 of open annular groove to be-1.7db, the high about 2.08dB of obvious RFID label antenna than imperforation cannelure.Can calculate according to above-mentioned formula (2), RFID label antenna of the present invention 9 obviously reads distance more than one times than the RFID label antenna of imperforation cannelure.

Based on above argumentation; The present invention has solved the remote read-write difficult problem of some ultrathin microband paste formula RFID label antennas at present; Make the distance that reads of RFID label antenna be improved, thereby can be used for the actual application environment that some have remote read-write needs.And the present invention is based on ultra-thin medium 1mm and following time design, the performance performance compares that other are the most obvious.Improve the bandwidth range of RFID label antenna simultaneously, made RFID label antenna of the present invention under bigger frequency range scope, to use.

The present invention only illustrates the set-up mode of open annular groove of the present invention with preferred embodiments, but execution mode of the present invention is not limited to this preferred embodiments.The second open annular groove among this embodiment also is not limited to overlap with the first open annular groove center, and the first open annular groove and the second open annular groove can be positioned at any position on the substrate base plate, and its opening also is not limited to the rightabout setting; Open annular groove of the present invention is not limited to be arranged on the center of the substrate base plate 3 of microband paste formula RFID label antenna 9; It can be formed at any position on the substrate base plate 3; Perhaps the first open annular groove 7 and the second open annular groove were arranged in 8 minutes, can realize that the coupling between the open annular groove gets final product; It is square that the overall appearance of open annular groove also is not limited to, and can also be set to rectangle, triangle or circular; It is two that open annular groove of the present invention also is not limited to, and it can be a plurality of, and the distribution form of a plurality of open annular grooves on the substrate base plate can be rule or irregular alignment.

Beneficial effect of the present invention is to reduce the resonance frequency of microband paste formula RFID label antenna 9; Effectively reduce antenna size; Improve the frequency bandwidth of microband paste formula RFID label antenna 9; And significantly improve the gain of microband paste formula RFID label antenna 9; Thereby can effectively improve the read-write distance of RFID label antenna 9, as far as being used for the microband paste formula RFID label antenna 9 on nonmetal, the reading/writing distance when increasing after the open annular groove of the present invention than the imperforation cannelure on the substrate base plate 3 improves more than 1 times at least.

The above; Be merely the detailed description of preferred embodiment of the present invention and graphic, characteristic of the present invention is not limited thereto, and all scopes of the present invention should be as the criterion with following scope; All embodiment that accords with the spirit variation similar of claim protection range of the present invention with it; All should be contained in the category of the present invention, anyly be familiar with this art in the field of the invention, can think easily and variation or adjustment all can be encompassed in following claim protection range of the present invention.

Claims (8)

1. a microband paste formula RFID label antenna comprises radiant panel (1), substrate (2) and substrate base plate (3), it is characterized in that:

Be formed with the first open annular groove (5) and the second open annular groove (7) on the described substrate base plate (3); Coupling through the said first open annular groove (5) and the second open annular groove (7); Reduce the resonance frequency of said RFID label antenna (9), improve the distance that reads of RFID label antenna (9).

2. RFID label antenna as claimed in claim 1 is characterized in that: the opening direction of the opening direction of the said first open annular groove (5) and the second open annular groove (7) is opposite.

3. RFID label antenna as claimed in claim 1 is characterized in that: the described first open annular groove (5) and the second open annular groove (7) are formed at any position on the substrate base plate (3).

4. RFID label antenna as claimed in claim 1 is characterized in that: the described second open annular groove (7) is positioned at the first open annular groove (5), and the center of the second open annular groove (7) and the first open annular groove (5) coincides.

5. RFID label antenna as claimed in claim 4 is characterized in that: the center and described RFID label antenna (9) center of the said described first open annular groove (5) and the second open annular groove (7) coincide.

6. RFID label antenna as claimed in claim 1 is characterized in that: the described first open annular groove (5) and the second open annular groove (7) are rectangle, square, triangle or circular.

7. RFID label antenna as claimed in claim 1 is characterized in that: the described first open annular groove (5) and the second open annular groove (7) are square.

8. RFID label antenna as claimed in claim 1 is characterized in that, the both sides of said substrate (2) also have short circuit face (4).

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