CN202103163U - Ultrahigh-frequency antenna of intelligent goods shelf RFID (radio frequency identification device) reader - Google Patents
Ultrahigh-frequency antenna of intelligent goods shelf RFID (radio frequency identification device) reader Download PDFInfo
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- CN202103163U CN202103163U CN2011201856711U CN201120185671U CN202103163U CN 202103163 U CN202103163 U CN 202103163U CN 2011201856711 U CN2011201856711 U CN 2011201856711U CN 201120185671 U CN201120185671 U CN 201120185671U CN 202103163 U CN202103163 U CN 202103163U
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Abstract
The utility model discloses an ultrahigh-frequency antenna of an intelligent goods shelf RFID (radio frequency identification device) reader. An upper PCB (printed circuit board) substrate and a lower PCB substrate are supported by nylon columns, the upper surface of the upper PCB substrate is provided with a plurality of upper surface metal conducting belts, the lower surface of the lower PCB substrate is provided with a plurality of lower surface metal conducting belts, the upper surface of the upper PCB substrate is covered by copper integrally, coaxial connectors, the upper surface metal conducting belts, the lower surface metal conducting belts and a matched load are serially connected through a conducting column, the width of each of the upper surface metal belts is gradually increased according to orders of signal transmission, and the sum of phase shift distances produced by the single upper surface metal conducting belt and the single lower surface metal conducting belt which are adjacent is integral multiple of the wavelength. The ultrahigh antenna of the intelligent goods shelf RFID reader is higher in current and uniform in distribution of magnetic fields on the upper portion thereof, and the antennas with different areas can be conveniently designed.
Description
Technical field
The invention belongs to the antenna structure design field, relate to a kind of rfid interrogator antenna.
Background technology
RFID (Radio Frequency Identification, radio frequency identification) technology is a kind of non-contacting automatic identification technology.Reading and writing device antenna plays key effect in rfid system.The frequency of reading and writing device antenna work has low frequency (below the 135kHz), high frequency (13.56MHz), hyperfrequency (860-960MHz) and microwave frequency band (more than the 2.4GHz) etc.Reading and writing device antenna is divided according to operating distance, can be divided near field antenna and far field antenna.The near field reading and writing device antenna that works in hyperfrequency is highly suitable for work in narrow space.Because near field antenna only just has stronger electromagnetic field in close, the intensity of distance electromagnetic fields far away slightly sharply weakens, and the far gain of this antenna is very low, so the large-area metal around the antenna can't exert an influence to the performance of antenna.
Because ultrahigh frequency band near field RFID reader-writer antenna has a lot of premium properties.But after the size of antenna surpassed a wavelength, near the magnetic field it just became inhomogeneous.The size that many correlative studys increase antenna has been done by a lot of companies and individual, and has product to come out, such as based on the antenna of coupling loop, the loop antenna of amounting to, lean on the loop antenna of lumped capacitor compensation of phase etc.The size of these antenna is still big inadequately, can't on large-scale shelf, produce the equally distributed electromagnetic field of large tracts of land.Document " RFID Smart Shelf with Confined Detection Volume at UHF, Carla R.Mederios, Jorge R.Costa; and Carlos A.Fernandes, IEEE Antennas and WirelessPropagation Letters, 2008; Vol.7; p773-776 " discloses a kind of shelf antenna of realizing with microstrip line, the change length that this antenna can be random, but width can not broaden.Document " Near-FieldAntenna for RFID Smart Shelfin UHF, Wonkyu Choi, Jeong-Seok Kim; Ji-Hoon Bae, Gilyoung Choi, and Jong-Suk Chae; Antennas andPropagation Society International Syposiuim, 2009, p1-4 " discloses another kind of shelf antenna; Be to adopt power splitter that feeder line is divided into the parallel microstrip line of a lot of roots, through a lot of roots slit on the floor electric field energy be coupled away then that this method is owing to there is power splitter; So the electric current on every line can reduce, therefore weakened the operating distance of antenna.
Summary of the invention
Adopt the deficiency that causes the electric current on the every line to reduce behind the power splitter in order to overcome prior art, the present invention provides a kind of hyper band intelligent commodity shelf rfid interrogator antenna, and this antenna can produce large-area equally distributed magnetic field.
The technical solution adopted for the present invention to solve the technical problems is: comprise PCB substrate, coaxial fitting and metal conduction band, upper strata PCB substrate and the PCB of lower floor substrate support through several nylon columns and form the air gap; The upper surface of upper strata PCB substrate has upper surface metal conduction band, and the lower surface of the PCB of lower floor substrate has lower surface metal conduction band, and the upper surface of the PCB of lower floor substrate is that integral body is covered copper; This integral body covers copper and the PCB of lower floor substrate, lower surface metal conduction band form microstrip line together, and this integral body covers copper and air gap, upper strata PCB substrate, upper surface metal conduction band form microstrip line together; Upper surface metal conduction band and lower surface metal conduction band all have many; And through alternately the link to each other end of upper surface metal conduction band and lower surface metal conduction band of conductive pole; With described upper surface metal conduction band and the series connection of lower surface metal conduction band; One end of first upper surface metal conduction band links to each other with coaxial fitting, and an end of last root upper surface metal conduction band connects matched load; Signal through upper surface metal conduction band and lower surface metal conduction band alternate transmission, arrives matched load from the coaxial fitting feed-in at last; The width of upper surface metal conduction band increases according to the order of signal transmission gradually; The degree that width increases is constant with the current value of each upper surface metal conduction band of flowing through to be criterion; The characteristic impedance of formed microstrip line reduces to matched load from the coaxial fitting junction gradually, even under the situation that has radiation loss to exist, still can keep the electric current on the upper surface metallic conduction constant like this; Upper surface metal conduction band motivates the magnetic field of tangential; Select the length of upper surface metal conduction band and lower surface metal conduction band; The phase-shift phase sum that adjacent single upper surface metal conduction band and single lower surface metal conduction band are produced is the integral multiple of wavelength; The tangential magnetic field that motivates of adjacent upper surface metal conduction band is a homophase like this, is superimposed, and forms large-area tangential magnetic field and distributes.
The invention has the beneficial effects as follows: do not adopt power splitter, but alternately be connected with lower surface metal conduction band through upper surface metal conduction band, the electric current on the upper surface metal conduction band is stronger like this; Change the length and the width that changes antenna of antenna, promptly the radical and the length of upper surface metal conduction band and lower surface metal conduction band are all little to the performance change of antenna, so can design the antenna of different area easily; Because the signal long-distance transmission has decay; And the width of upper surface metal conduction band increases gradually, has reduced the characteristic impedance of microstrip line, has offset the decay of signal; Make the CURRENT DISTRIBUTION on upper surface metal conduction band not reduce, so the Distribution of Magnetic Field on antenna top is even.
Below in conjunction with accompanying drawing and embodiment the present invention is further specified.
Description of drawings
Fig. 1 is a hyper band intelligent commodity shelf rfid interrogator antenna structure view of the present invention.
Fig. 2 is the top view of Fig. 1.
Fig. 3 is the end view of Fig. 1.
Among the figure, 1, coaxial fitting, 2, upper strata PCB substrate, 3, the PCB of lower floor substrate, 4, upper surface metal conduction band, 5, lower surface metal conduction band, 6, conductive pole, 7, nylon column, 8, the air gap, 9, matched load, 10, integral body covers copper.
Embodiment
With reference to Fig. 1～3, the present invention is covered copper 10 by coaxial fitting 1, upper strata PCB substrate 2, the PCB of lower floor substrate 3, upper surface metal conduction band 4, lower surface metal conduction band 5, conductive pole 6, nylon column 7, air gap 8, matched load 9 and integral body and is formed.
In the present embodiment, the width of upper strata PCB substrate 2 and the PCB of lower floor substrate 3 is 350mm, and length is 700mm, and thickness is 2mm, and material is FR4.Two PCB substrates form air gap 8 through highly being nylon column 7 supports of 10mm on four angles.
Article one, the width on upper surface metal conduction band 4 left sides is 52mm, and the width on the right is 55 millimeters; The width on second upper surface metal conduction band 4 left sides is 55mm, and the width on the right is 58 millimeters; Article three, the width on upper surface metal conduction band 4 left sides is 58mm, and the width on the right is 62 millimeters.The characteristic impedance of covering three microstrip lines that copper 10, air gap 8, upper strata PCB substrate 2 and upper surface metal conduction band 4 formed by integral body like this carries out the transition to last 44 ohm by 50 ohm through 48 ohm and 46 ohm.The impedance of the last matched load 9 that is connected is 44 ohm and microstrip line coupling.
Article one, the width of lower surface metal conduction band 5 is 4.2mm, and characteristic impedance is 48 ohm, connects article one and second upper surface metal conduction band 4 through two conductive poles 6.The width of second lower surface metal conduction band 5 is 4.5mm, and characteristic impedance is 46 ohm, connects second and the 3rd upper surface metal conduction band 4 through two conductive poles 6.
If the width of upper surface metal conduction band 4 and lower surface metal conduction band 5 does not have gradual change, the characteristic impedance of so formed microstrip line all is 50 ohm.The reduction of amplitude through taking place in signal after the long Distance Transmission of microstrip line, this mainly is the radiation loss that far produces owing to upper surface metal conduction band 4 and the whole distance of covering copper 10.Electric current on the upper surface metal conduction band 4 reduces gradually, must cause field weakening on every side, has influenced the distance that reads of antenna.Therefore in the present invention, the width of upper surface metal conduction band 4 increases gradually, and the characteristic impedance of microstrip line reduces gradually, has kept constant along the current amplitude of upper surface metal conduction band 4 like this, and then magnetic field intensity is stable.
In the present embodiment, signal flows into lower surface metal conduction band 5 through upper surface metal conduction band 4 backs through conductive pole 6 to the right, behind left end, flows into next root upper surface metal conduction band 4 through conductive pole 6 again.Single upper surface metal conduction band 4 is six wavelength with the phase shift that single lower surface metal conduction band 5 common properties are given birth to, so the electric current on the adjacent upper surface metal conduction band 4 all is a homophase.The tangential magnetic field that above antenna, produces of upper surface metal conduction band 4 superposes in the same way like this.
Should be understood that the above is merely a kind of embodiment of the present invention.Concerning those of ordinary skills, can increase or reduce the radical of upper surface metal conduction band 4 and lower surface metal conduction band 5 easily, to change the width of antenna; Also can increase or reduce the length of antenna, as long as guarantee that single upper surface metal conduction band 4 and the phase-shift phase that single lower surface metal conduction band 5 produces are the integral multiple of wavelength; The also passable upper strata PCB substrate 2 and the PCB of lower floor substrate 3 of selecting other material for use; Also can choose the height of different nylon column 7, to produce the air gap 8 of different-thickness.
Claims (1)
1. a hyper band intelligent commodity shelf rfid interrogator antenna comprises PCB substrate, coaxial fitting and metal conduction band, it is characterized in that: upper strata PCB substrate and the PCB of lower floor substrate support through several nylon columns and form the air gap; The upper surface of upper strata PCB substrate has upper surface metal conduction band, and the lower surface of the PCB of lower floor substrate has lower surface metal conduction band, and the upper surface of the PCB of lower floor substrate is that integral body is covered copper; Upper surface metal conduction band and lower surface metal conduction band all have many; And through alternately the link to each other end of upper surface metal conduction band and lower surface metal conduction band of conductive pole; With described upper surface metal conduction band and the series connection of lower surface metal conduction band; One end of first upper surface metal conduction band links to each other with coaxial fitting, and an end of last root upper surface metal conduction band connects matched load; The width of upper surface metal conduction band increases according to the order of signal transmission gradually; The degree that increases is constant with the current value of each upper surface metal conduction band of flowing through to be criterion; The length of upper surface metal conduction band and lower surface metal conduction band, the phase-shift phase sum that adjacent single upper surface metal conduction band and single lower surface metal conduction band are produced is the integral multiple of wavelength.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011201856711U CN202103163U (en) | 2011-06-02 | 2011-06-02 | Ultrahigh-frequency antenna of intelligent goods shelf RFID (radio frequency identification device) reader |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011201856711U CN202103163U (en) | 2011-06-02 | 2011-06-02 | Ultrahigh-frequency antenna of intelligent goods shelf RFID (radio frequency identification device) reader |
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| Publication Number | Publication Date |
|---|---|
| CN202103163U true CN202103163U (en) | 2012-01-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011201856711U Expired - Fee Related CN202103163U (en) | 2011-06-02 | 2011-06-02 | Ultrahigh-frequency antenna of intelligent goods shelf RFID (radio frequency identification device) reader |
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| CN (1) | CN202103163U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102299413A (en) * | 2011-06-02 | 2011-12-28 | 西北工业大学 | UHF (ultra high frequency) RFID (radio frequency identification) reader-writer antenna of smart shelf |
| WO2015024223A1 (en) * | 2013-08-21 | 2015-02-26 | Zhang Wei | Intelligent safe box, safe control system and control method using same |
| CN108629386A (en) * | 2018-03-30 | 2018-10-09 | 厦门致联科技有限公司 | A kind of shelf of automatic identification commodity purchasing behavior |
-
2011
- 2011-06-02 CN CN2011201856711U patent/CN202103163U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102299413A (en) * | 2011-06-02 | 2011-12-28 | 西北工业大学 | UHF (ultra high frequency) RFID (radio frequency identification) reader-writer antenna of smart shelf |
| WO2015024223A1 (en) * | 2013-08-21 | 2015-02-26 | Zhang Wei | Intelligent safe box, safe control system and control method using same |
| CN108629386A (en) * | 2018-03-30 | 2018-10-09 | 厦门致联科技有限公司 | A kind of shelf of automatic identification commodity purchasing behavior |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120104 Termination date: 20140602 |