CN203553353U - A radio frequency identification fractal antenna - Google Patents

A radio frequency identification fractal antenna Download PDF

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Publication number
CN203553353U
CN203553353U CN201320636936.4U CN201320636936U CN203553353U CN 203553353 U CN203553353 U CN 203553353U CN 201320636936 U CN201320636936 U CN 201320636936U CN 203553353 U CN203553353 U CN 203553353U
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China
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branch
antenna
fractal
trunk
radiation patch
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CN201320636936.4U
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Chinese (zh)
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刘国
张海光
张辉
王毅
徐良
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Xidian University
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Xidian University
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Abstract

The utility model discloses a radio frequency identification fractal antenna comprising a radiation paster (2), a coaxial feed line (3) and an antenna base plate (4). The radio frequency identification fractal antenna is characterized in that: a tree-branch-shaped meta-material medium plate (1) is arranged between the radiation paster (2) and the antenna base plate (4). M rows and N columns of tree-branch-shaped array units (5) of a same shape are etched in both the upper and lower surfaces of the medium plate (1), wherein the M>=2, and the N>=2. The units all employ fractal structures with self-similarity characteristics. The fractal structures with the self-similarity characteristics have the shapes similar to tree branches. Each fractal structure comprises four braches which are intersecting in a cross-shaped mode. Each branch is composed of a trunk and two branches perpendicular to the trunk. A first branch c, relatively close to a cross intersection portion, is positioned at the left side of the trunk a. A second branch b, relatively far away from the cross intersection portion, is positioned at the right side of the trunk a. The antenna of the utility model has advantages of a low standing-wave ratio, a high gain, a good directional diagram and high radiation efficiency. The antenna of the utility model can be used to radio frequency identification communication systems in China.

Description

Radio-frequency (RF) identification fractal antenna
Technical field
The utility model belongs to and relates to antenna technical field, and particularly a kind of radio-frequency (RF) identification fractal antenna, can be used for non-contacting bidirectional data communication.
Background technology
Radio frequency discrimination RFID, is that one is carried out non-contacting bidirectional data communication by wireless radio frequency mode, target is identified and obtained the automatic identification technology of related data.RFID has been penetrated into the every field of people's daily life now, and its application comprises asset management, personnel gate inhibition, logistics etc.In rfid system, RFID label antenna has critical impact to the working index of whole wireless communication system.In the uhf band that China announces, RFID frequency range is 840～845MHz and two frequency ranges of 920～925MHz.Traditional RFID antenna has a variety of forms, such as right-angled intersection antenna, and dipole antenna, both arms helical antenna, microstrip antenna, wherein microstrip antenna is due to its low section, and cost is low, and volume is little etc., and advantage is most widely used.For meeting read write line RFID antenna, work in the requirement of 840～845MHz and two frequency ranges of 920～925MHz, if directly adopt traditional microstrip antenna designs, the bandwidth that exists antenna is narrow, can not meet the requirement that two frequency ranges are worked simultaneously.Traditional realize double frequency with multi resonant shake, the method such as slotted line, double applying sheet, these technology mainly realize double frequency-band work by changing radiation patch, design is complicated, and radiation efficiency is subject to certain impact.
Summary of the invention
Main purpose of the present utility model is the deficiency for above-mentioned prior art, proposes a kind of radio-frequency (RF) identification fractal antenna, with simplified structure, improves radiation efficiency, meets the job requirement of 840～845MHz and two frequency ranges of 920～925MHz.
The technical solution of the utility model is such:
One. know-why
In recent years, some artificial materials with distinct electrical magnetic characteristic became one, electromagnetism field study hotspot, as electro-magnetic bandgap EBG structure, and defect ground structure DGS, left hand medium LHM, frequency-selective surfaces FSS etc.These materials are referred to as " Metamaterials ", i.e. " super material " or " super clever material ".These materials are all synthetic materials, all show some in the non-existent phenomenon of occurring in nature, picture frequency rate forbidden band, negative index etc. in electromagnetism field.When they being applied in microwave and millimeter wave engineering field, can significantly improve the performance of some equipment and device, as improved antenna gain, increase the beamwidth of antenna, reduce to be coupled between array element, manufacture high Q resonant cavity etc.The appearance of these artificial materials, provides possible solution for overcoming some technical bottlenecks that run in current antenna, the communications field.
The utility model utilizes the frequency forbidden band characteristic of described " super material ", designed a kind of tree-shaped super material, it is the dielectric-slab that above and below is etched with dendroid fractal structure simultaneously, when electromagnetic wave is during perpendicular to two-sided dendritic structure array incident, magnetic field can produce induced current between branch, thereby introduces inductance.Between positive and negative branch, there is gap, thereby produce electric capacity, then produced the LC resonance relevant with the physical dimension of branch, thus produced a transmission forbidden band, obtain negative magnetoconductivity.According to Electromagnetic Simulation software Ansoft HFSS analog result, branch length at different levels are chosen larger, and live width is narrower, and the dielectric constant of baseplate material is larger, and the resonance frequency that produces negative magnetoconductivity is just lower.Therefore, can be by controlling each branch length of branch, the dielectric constant of dielectric-slab, and the distance between unit, realize the transmission forbidden band of different frequent points, the super material medium plate of design is placed in the middle of radiation patch and Antenna baseplate, by the position of rational adjustment fractal structure and base plate, make two frequency bands of antenna resonance cover respectively 840 required～845MHz of China RFID and two frequency ranges of 920～925MHz, avoid slotted line and the double-deck microstrip antenna of piling up that tradition is complicated, by keeping radiation patch area constant, improve radiation efficiency simultaneously.
Two. antenna structure
In order to realize utility model object, the utility model comprises radiation patch 2, coaxial feeder 3 and Antenna baseplate 4, it is characterized in that: between radiation patch 2 and Antenna baseplate 4, be provided with the super material medium plate 1 of dendroid, the upper and lower faces of this dielectric-slab 1 is all etched with the identical dendroid array element 5 of the capable N row of M shape, M >=2, N >=2, each unit all adopts the fractal structure with self-similarity characteristics;
The fractal structure of described self-similarity characteristics, be similar to branch shape, it comprises the branch of four right-angled intersections, each branch is comprised of with the Liang Ge branch vertical with trunk a trunk, and the first c of branch from right-angled intersection point close to is positioned at the left side of trunk a, the second b of branch from right-angled intersection point away from is positioned at the right side of trunk a.
Above-mentioned radio-frequency (RF) identification fractal antenna, is characterized in that: the distance S of the first c of branch and right-angled intersection point 1with the distance S of the second b of branch to the first c of branch 2equate, and a=3b=3c, 1mm≤S 1≤ 10mm.
Above-mentioned radio-frequency (RF) identification fractal antenna, is characterized in that: the capable N row of the M dendroid array element of dielectric-slab upper and lower faces strictly aligns, and the dendroid array element of two faces is overlapping at vertical space face.
Above-mentioned radio-frequency (RF) identification fractal antenna, is characterized in that: described radiation patch and Antenna baseplate all adopt metal rectangular paster, and Antenna baseplate is greater than radiation patch.
Above-mentioned radio-frequency (RF) identification fractal antenna, is characterized in that: coaxial feeder carries out feed through Antenna baseplate in a side of radiation patch.
The utlity model has following advantage:
1) the utility model is owing to adopting the super material medium plate of dendroid, and the tree-shaped super material medium plate of design is placed between radiation patch and Antenna baseplate, can realize negative magnetoconductivity by controlling super material medium plate, thereby utilize the transmission forbidden band characteristic of super material medium plate to realize the work of antenna two-band, avoid the loaded down with trivial details technology such as complicated slotted line and stack paster, be easy to processing, debugging and batch production.
2) the utility model antenna is owing to adopting super material medium plate to realize two-band work, radiation patch used is not through technology such as fluting, corner cuts, so the area of radiation patch is consistent with the radiation patch size of air microstrip aerial, thereby guaranteed higher antenna radiation efficiency.
By actual measurement, show, the utility model antenna has good radiation characteristic, covers two frequency ranges of 840 required～845MHz of Chinese radio frequency discrimination RFID and 920～925MHz completely.
Accompanying drawing explanation
Fig. 1 is structural front view of the present utility model,
Fig. 2 is structure side view of the present utility model;
Fig. 3 is super material medium plate Fractal array schematic diagram of the present utility model;
Fig. 4 is the magnetic permeability figure of the super material medium plate of the utility model, and solid line represents real part, and dotted line represents imaginary part;
Fig. 5 is antenna standing wave ratio measured drawing of the present utility model;
Fig. 6 is antenna two-band actual measurement directional diagram of the present utility model; The directional diagram that wherein Fig. 6 (a) is f=843MHz, the directional diagram that Fig. 6 (b) is f=923MHz.
Embodiment
See figures.1.and.2, the utility model comprises the super material medium plate 1 of dendroid, radiation patch 2, coaxial feeder 3 and Antenna baseplate 4.The super material medium plate 1 of dendroid is placed between radiation patch 2 and Antenna baseplate 4, and fixes by foam.Radiation patch 2 and Antenna baseplate 4 are metal rectangular paster, and Antenna baseplate 4 is greater than radiation patch 2.Coaxial feeder 3 carries out feed through Antenna baseplate 4 in a side of radiation patch 2, and the crust of coaxial feeder is connected on Antenna baseplate 4, and the heart yearn of coaxial feeder is connected in radiation patch, forms air microstrip paster antenna.
With reference to Fig. 3, the super material medium plate 1 of described dendroid, its upper and lower faces is all etched with the identical dendroid array element 5 of the capable N row of M shape, M >=2, N >=2, each unit 5 all adopts the fractal structure with self-similarity characteristics.The fractal structure of this self-similarity characteristics, be similar to branch shape, it comprises the branch of four right-angled intersections, each branch is comprised of with the Liang Ge branch vertical with trunk a trunk, and the first c of branch from right-angled intersection point close to is positioned at the left side of trunk a, the second b of branch from right-angled intersection point away from is positioned at the right side of trunk a.The distance S of this c of the first branch and right-angled intersection point 1with the distance S of the second b of branch to the first c of branch 2equate, and a=3b=3c, 1mm≤S 1≤ 50mm.By adjusting distance d between size, the unit of each unit 5 and the dielectric constant of dielectric-slab, can realize the negative magnetoconductivity of dielectric-slab, to realize transmission forbidden band, thereby form super material medium plate, and then realize the two-band work of antenna.
Below provide the embodiment of the utility model antenna different parameters:
Implement 1.
Radiation patch 2 of the present utility model and Antenna baseplate 4 adopt rectangle copper sheet, and the length and width of radiation patch 2 is respectively L 1=146mm, W 1=130mm, the length and width of Antenna baseplate 4 is respectively L 2=270mm, W 2=212mm.The super material medium plate 1 of dendroid adopts circuit board lithographic technique, in size, is that 120mm × 120mm, thickness are the ptfe substrate above and below etching tree of 1.5mm, DIELECTRIC CONSTANT ε=2.33, and the dendroid array element 5 on two sides strictly aligns.By Electromagnetic Simulation software HFSS, optimize, preferably: trunk a=9mm, the first c=3mm of branch, the second b=3mm of branch, the distance d=21.5mm between array element 5, the distance H of tree-shaped super material medium plate 1 and Antenna baseplate 4 1=9mm, the distance between radiation patch 2 and Antenna baseplate 4 is H 2=18mm, angle theta=90 ° between two branches.
Implement 2.
Radiation patch 2 of the present utility model and Antenna baseplate 4 adopt rectangle iron plate, and the length and width of radiation patch 2 is respectively L 1=146mm, W 1=130mm, the length and width of Antenna baseplate 4 is respectively L 2=270mm, W 2=212mm.The super material medium plate 1 of dendroid adopts circuit board lithographic technique, in size, is that 128mm × 128mm, thickness are the medium substrate above and below etching tree of 1.6mm, DIELECTRIC CONSTANT ε=2.13, and the dendroid array element 5 on two sides strictly aligns.By Electromagnetic Simulation software HFSS, optimize, preferably: trunk a=9.6mm, the first c=3.2mm of branch, the second b=3.2mm of branch, the distance d=22.5mm between array element 5, the distance H of tree-shaped super material medium plate 1 and Antenna baseplate 4 1=9mm, the distance between radiation patch 2 and Antenna baseplate 4 is H 2=18mm, angle theta=90 ° between two branches.
Implement 3.
Radiation patch 2 of the present utility model and Antenna baseplate 4 adopt rectangle aluminium flake, and the length and width of radiation patch 2 is respectively L 1=146mm, W 1=130mm, the length and width of Antenna baseplate 4 is respectively L 2=270mm, W 2=212mm.The super material medium plate 1 of dendroid adopts circuit board lithographic technique, in size, is that 130mm × 130mm, thickness are the medium substrate above and below etching tree of 1.7mm, DIELECTRIC CONSTANT ε=2.02, and the dendroid array element 5 on two sides strictly aligns.By Electromagnetic Simulation software HFSS, optimize, preferably: trunk a=10.5mm, the first c=3.5mm of branch, the second b=3.5mm of branch, the distance d=25.5mm between array element 5, the distance H of tree-shaped super material medium plate 1 and Antenna baseplate 4 1=9mm, the distance between radiation patch 2 and Antenna baseplate 4 is H 2=18mm, angle theta=90 ° between two branches.
Effect of the present utility model can illustrate by following test data:
Test 1: test its S parameter at microwave dark room with Agilent vector network analyzer 8753ES, then counter spreading out metamaterial structure magnetic permeability, and result as shown in Figure 4.As can be seen from Figure 4, the metamaterial structure of the utility model antenna magnetic permeability in 878～910MHz is negative value, has transmission forbidden band characteristic.
Test 2: in Agilent vector network analyzer 8753ES test antenna standing-wave ratio for microwave dark room, frequency range 700MHz～1000MHz is set on instrument, measured result as shown in Figure 5.As can be seen from Figure 5, the utility model antenna is at the standing-wave ratio of required frequency range 840～845MHz and 920～925MHz: VSWR≤2:1.
Test 3: Airlink3D microwave dark room measure antenna pattern, measured result as shown in Figure 6, the directional diagram that wherein Fig. 6 (a) is f=843MHz, the directional diagram that Fig. 6 (b) is f=923MHz, dotted line represents E face, solid line represents H face.The utility model antenna all has good directional diagram at two working frequency range as seen from Figure 6.
More than describing is only a concrete example of the present utility model; do not form any restriction of the present utility model; obviously for those skilled in the art; understanding after the utility model content and principle; all may be in the situation that not deviating from the utility model principle, structure; carry out various corrections and change in form and details, but these corrections based on the utility model thought and changing still within claim protection range of the present utility model.

Claims (5)

1. a radio-frequency (RF) identification fractal antenna, comprises radiation patch (2), coaxial feeder (3) and Antenna baseplate (4), it is characterized in that:
Between radiation patch (2) and Antenna baseplate (4), be provided with the super material medium plate of dendroid (1), the upper and lower faces of this dielectric-slab (1) is all etched with the dendroid array element (5) that the capable N row of M shape is identical, M >=2, N >=2, each unit all adopts the fractal structure with self-similarity characteristics;
The fractal structure of described self-similarity characteristics, be similar to branch shape, it comprises the branch of four right-angled intersections, each branch is comprised of with the Liang Ge branch vertical with trunk a trunk, and the first c of branch from right-angled intersection point close to is positioned at the left side of trunk a, the second b of branch from right-angled intersection point away from is positioned at the right side of trunk a.
2. radio-frequency (RF) identification fractal antenna according to claim 1, is characterized in that: the distance S of the first c of branch and right-angled intersection point 1with the distance S of the second b of branch to the first c of branch 2equate, and a=3b=3c, 1mm≤S 1≤ 50mm.
3. radio-frequency (RF) identification fractal antenna according to claim 1, is characterized in that: the capable N row of the M dendroid array elements (5) of dielectric-slab (1) upper and lower faces strictly align, and the dendroid array element of two faces is overlapping at vertical space face.
4. radio-frequency (RF) identification fractal antenna according to claim 1, is characterized in that: described radiation patch (2) and Antenna baseplate (4) all adopt metal rectangular paster, and Antenna baseplate (4) is greater than radiation patch (2).
5. radio-frequency (RF) identification fractal antenna according to claim 1, is characterized in that: coaxial feeder (3) carries out feed through Antenna baseplate (4) in a side of radiation patch (2).
CN201320636936.4U 2013-10-15 2013-10-15 A radio frequency identification fractal antenna Withdrawn - After Issue CN203553353U (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103531898A (en) * 2013-10-15 2014-01-22 西安电子科技大学 Supermaterial-based radio frequency identification fractal antenna
WO2018231844A1 (en) * 2017-06-12 2018-12-20 Fractal Antenna Systems, Inc. Parasitic antenna arrays incorporating fractal metamaterials
CN109638466A (en) * 2018-12-27 2019-04-16 黑龙江工程学院 A kind of Meta Materials frequency selection surface texture for improving ultra-wideband antenna gain
US11128052B2 (en) 2017-06-12 2021-09-21 Fractal Antenna Systems, Inc. Parasitic antenna arrays incorporating fractal metamaterials

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103531898A (en) * 2013-10-15 2014-01-22 西安电子科技大学 Supermaterial-based radio frequency identification fractal antenna
CN103531898B (en) * 2013-10-15 2016-04-13 西安电子科技大学 Based on the radio-frequency (RF) identification fractal antenna of Meta Materials
WO2018231844A1 (en) * 2017-06-12 2018-12-20 Fractal Antenna Systems, Inc. Parasitic antenna arrays incorporating fractal metamaterials
US10381738B2 (en) 2017-06-12 2019-08-13 Fractal Antenna Systems, Inc. Parasitic antenna arrays incorporating fractal metamaterials
US11128052B2 (en) 2017-06-12 2021-09-21 Fractal Antenna Systems, Inc. Parasitic antenna arrays incorporating fractal metamaterials
CN109638466A (en) * 2018-12-27 2019-04-16 黑龙江工程学院 A kind of Meta Materials frequency selection surface texture for improving ultra-wideband antenna gain

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AV01 Patent right actively abandoned

Granted publication date: 20140416

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C25 Abandonment of patent right or utility model to avoid double patenting