CN207134470U - A kind of ultra-high frequency RFID label antenna of T-shaped matching impedance structure - Google Patents

Abstract

The utility model have developed a kind of ultra-high frequency RFID label antenna of T-shaped matching impedance structure, be related to RFID field of radio frequency identification.Antenna described in the utility model is by designing T-shaped matching（T‑Match）The size of impedance structure, impedance matching, described T-shaped matching can be realized with described folded dipole（T‑Match）Impedance module is two symmetrical L-type compositions, and two L-types are long 11.5 millimeters, high 5 millimeters, width is 1.5 millimeters, described T-shaped matching（T‑Match）Impedance structure is easily controllable to the amplitude distribution in antenna opening diametric plane, and bore face utilization rate is high, small volume, it is easy to accomplish Sidelobe or extremely low secondary lobe.UHF RFID antenna design described in the utility model is simply firm, and feed is convenient, is adapted to batch production.

Description

A kind of ultra-high frequency RFID label antenna of T-shaped matching impedance structure

Technical field

It the utility model is related to radio frequency discrimination RFID field, and in particular to a kind of hyperfrequency of T-shaped matching impedance structure RFID label antenna.

Background technology

Super high frequency radio frequency identifies（UHF RFID）Technology is state-of-the-art forth generation automatic identification technology in the world, is near several Year just starts to rise and obtain a new technology of rapid popularization and application, and it has remote identification distance, recognition accuracy height, known Other speed is fast, strong antijamming capability, service life are long, can penetrate nonmetallic materials, the features such as operation strategies are wide.It is to realize Digitlization, a kind of information-based and brand-new pipe that the characteristic such as the attribute to object, state, numbering progress automatic data collection is released Reason means, it can be widely applied to the identity automatic identification of personnel, animal or article etc..Therefore current super high frequency radio frequency identification （UHF RFID）The development of technology is the emphasis of REID development.

Typical super high frequency radio frequency identification（UHF RFID）System includes label, read write line and application system.Wherein label It is made up of label antenna and label chip.Label antenna is mainly used in receiving the radiofrequency signal that launches of read write line and by its turn Energy is turned to, the energy of acquisition is powered for label chip.Identified in super high frequency radio frequency（UHF RFID）In system, label antenna matter The quality of amount is directly connected to the performance of whole system, therefore good UHF RFID tag Antenna Design is very important. Different according to application environment in electronic tag field, the requirement to label antenna is also different, is answered so designing suitable for different Also turn into an important topic with the antenna of environment.

Current China ultrahigh frequency electronic tag working frequency is 860MHz~960MHz, and the working method used is electromagnetic wave Propagate coupling.Reading and writing device antenna provides RF energy for label, and label antenna receives RF energy and by the electronic code of label Information is sent to read write line by way of backscattered modulation.Labeling task in the far field of reading and writing device antenna, maximum read away from From generally higher than 1m, representative value is 3~8m, maximum up to 10m.It can be seen that reading/writing distance is mainly by label antenna back-scattered signal Power level determine.The challenge of tag antenna design mainly has 3 aspects：The less appearance and size of label antenna；Antenna increases Benefit, i.e., under conditions of input power is equal, actual antennas is with preferable radiating element in letter caused by the same point of space Number power density with the external world change；Impedance matching between label chip and label antenna, influence power and maximize transmission.

At present, some label antennas are in order to overcome appearance and size to significantly limit the design of matching network, to label day The lifting of line input reactance is inadequate, it is impossible to forms conjugation with high condensance and the low resistance output impedance of RFID label chip Match somebody with somebody, reduce the gain problem of antenna, design V types dipole antenna, inverted f type antenna or fractal antenna etc..The profile of these antenna Profile is mostly the deformation of half-wave dipole, and length is about the half of wavelength, it is difficult to impedance matching is fully achieved, and its band width It is narrow, it is difficult to integrated.For upper above-mentioned problem, the utility model provides a kind of hyperfrequency of T-shaped matching impedance structure RFID label antenna.

Utility model content

The utility model have developed a kind of ultra-high frequency RFID label antenna of T-shaped matching impedance structure, by changing T-shaped Match somebody with somebody（T-Match）The size of impedance structure, it can be good at realizing impedance matching, simple in construction firmly feed is convenient, fits Close batch production.

The technical solution of the utility model is：

A kind of ultra-high frequency RFID label antenna of T-shaped matching impedance structure, including folded dipole, T-shaped matching（T- Match）Impedance module, feed port, substrate.

Described 78 millimeters of folded dipole overall length, the radius of lower arcuate are 2 millimeters, and middle transverse part grows 30 millimeters, Described folded doublet gain reaches 2.2dbi.

Described T-shaped matching（T-Match）Impedance module is two symmetrical L-types compositions, two L-types be it is long 11.5 millimeters, High 5 millimeters, width is 1.5 millimeters.

Described feed port sets the excitation of lump port（lumped port）, port is arranged on internal system, feed end Mouth is used for chip placement, carries out reverse packaging process or binding technique, chip are connected with antenna.

Described substrate uses FR4 materials, a length of 89 millimeters, wide 12 millimeters, 1.6 millimeters of thickness.

Brief description of the drawings

Fig. 1 is structure chart of the present utility model.

The T-shaped matching of a folded dipoles, b（T-Match）Impedance module, c feed ports, d substrates.

Embodiment

The utility model is described in further detail with reference to Fig. 1.

As shown in figure 1, a kind of ultra-high frequency RFID label antenna of T-shaped matching impedance structure of the utility model folds comprising a The T-shaped matching of dipole, b（T-Match）Impedance module, c feed ports, d substrates.

As shown in figure 1, first designing folded dipole a, folded dipole a is bilateral symmetry, minister a1 9mm, width 2mm；Minister a2 4mm, width 1.3mm；Minister a3 7mm, width 1.3mm；A4 half arc portion radius 2mm, width 1.3mm；Minister a5 4mm, width 1.3mm；The long 30mm of a6, width 1.3mm, using the size, material copper, copper thickness 0.035mm, the gain energy of antenna Reach 2.2dbi.

As shown in figure 1, T-shaped impedance matching is determined according to folded dipole a（T-Match）Module b, T-shaped matching（T- Match）B is bilateral symmetry, and left side structure is ' L' types, and two L-types are that long 11.5mm, high 5mm, width are 1.5mm.T-shaped impedance matching（T-Match）Module b and feed port c forms radiation patterns characteristic, and chip is attached to rectangle feed end Mouth c openings carry out effectively transmitted signal energy, and the signal that antenna is received is sent to die terminals with the loss of minimum.Together When chip can control T-Match folded dipole a, the signal that reflection receivable arrives, the requirement of high inductive reactance can be met, can to Distribution network is suitably modified, and increases the matching degree of antenna and chip.

Distributing point c position is set to be selected in T-shaped impedance matching as shown in Figure 1（T-Match）Among module b, long 1mm, width 1.5mm, according to this tag emulation, the setting of feed port c excitations is encouraged using lump port（lumped port）Mode.Collection Total port excitation（lumped port）Excitation in the form of voltage or electric current, be added on a point or unit, port edge does not have There is the part being in contact with conductor or other ports, default boundary condition is preferable magnetic border, therefore is arrived in the absence of field coupling Ripple port edge influences the problem of transmission line characteristics.Need to set quad lines or tag wire for this model, while at excitation end User can set port Impedance according to antenna performance in mouthful, and this label antenna resistance is 38.4, reactance 293.7.Complete Label chip can be welded in label feed port c by this label antenna after making, and form label.

As shown in figure 1, substrate d serves as medium, a length of wide 12mm thickness 1.6mm of 89mm, using FR4 materials, this antenna Substrate is using FR4 materials, relative atmospheric dielectric constant 4.4~4.6, dielectric loss tangent 0.02.According to Principle of Antenna Can obtain, λ be free space wavelength, λ g be antenna on wavelength, ε r be dielectric substrate relative dielectric constant, λ g=λ/, From formula, the size of antenna, into positive correlation, therefore selects suitable substrate effectively to reduce the chi of antenna with λ g It is very little.

In uhf band, current China's ultrahigh frequency electronic tag work covering frequence scope is for electronic label antenna use 860MHz~960MHz, it is 915MHz to set its resonant frequency of the utility model electronic label antenna.The slot antenna of design exists During centre frequency 915MHz, the loss of its aerial signal reflection coefficient of port has reached minimum value -58db, in 860M ~ 960M frequency model In enclosing, reflectance factor is both less than -20dbm, and the energy for the energy 99% that antenna receives can be delivered to chip, in 915M frequency Under, energy that antenna receives, 99.85% can be delivered to chip.

Label antenna maximum gain described in the utility model is 2.2dBi, the upper antenna energy of chip connection and read write line（Work( Rate 30dbm, antenna 8dBi）Communication, communication distance reach 10m.

Claims (4)

1. a kind of ultra-high frequency RFID label antenna of T-shaped matching impedance structure, including folded dipole, T-shaped matching（T-Match） Impedance module, feed port, substrate, it is characterised in that described T-shaped matching（T-Match）Impedance module is two symmetrical L-type groups Into two L-types are long 11.5 millimeters, high 5 millimeters, width is 1.5 millimeters, 0.035 millimeter of thickness.

A kind of 2. ultra-high frequency RFID label antenna of T-shaped matching impedance structure according to claim 1, it is characterised in that Described 78 millimeters of folded dipole overall length, the radius of lower arcuate are 2 millimeters, and middle transverse part grows 30 millimeters, described folding Folded dipole antenna gain reaches 2.2dbi.

A kind of 3. ultra-high frequency RFID label antenna of T-shaped matching impedance structure according to claim 1, it is characterised in that Described feed port sets the excitation of lump port（lumped port）, port is arranged on internal system, and feed port is used for putting Chip is put, reverse packaging process is carried out or binding technique, chip is connected with antenna.

A kind of 4. ultra-high frequency RFID label antenna of T-shaped matching impedance structure according to claim 1, it is characterised in that Described substrate uses FR-4 materials, a length of 89 millimeters, wide 12 millimeters, 1.6 millimeters of thickness.