CN107392298B - 一种基于角度定位的全向无芯片rfid标签 - Google Patents

一种基于角度定位的全向无芯片rfid标签 Download PDF

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CN107392298B
CN107392298B CN201710692659.1A CN201710692659A CN107392298B CN 107392298 B CN107392298 B CN 107392298B CN 201710692659 A CN201710692659 A CN 201710692659A CN 107392298 B CN107392298 B CN 107392298B
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CN107392298A (zh
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刘雄英
王泽众
韦岗
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South China University of Technology SCUT
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    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06KGRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/077Constructional details, e.g. mounting of circuits in the carrier
    • G06K19/07749Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
    • G06K19/07771Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card the record carrier comprising means for minimising adverse effects on the data communication capability of the record carrier, e.g. minimising Eddy currents induced in a proximate metal or otherwise electromagnetically interfering object
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    • G06COMPUTING; CALCULATING OR COUNTING
    • G06KGRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/0716Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips at least one of the integrated circuit chips comprising a sensor or an interface to a sensor
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06KGRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/077Constructional details, e.g. mounting of circuits in the carrier
    • G06K19/07749Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
    • G06K19/07773Antenna details
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

本发明公开了一种基于角度定位的全向无芯片RFID标签,包括天线辐射贴片结构及介质基板结构,所述天线辐射贴片结构位于介质基板结构的上表面,所述天线辐射贴片结构由矩形贴片构成,所述矩形贴片印制有上方编码单元及下方定位单元,所述下方定位单元位于上方编码单元的正下方。本发明具有全向性、小型化、大容量、高频谱利用率、易印刷等优点,适用于物联网领域。

Description

一种基于角度定位的全向无芯片RFID标签
技术领域
本发明涉及物联网领域,具体涉及一种基于角度定位的全向无芯片RFID标签。
背景技术
射频识别(Radio Frequency Identification,RFID)技术相对于条形码、智能卡等识别技术具有优势。RFID可以自动识别不同物体上附着的标签,通过标签与阅读器之间的电磁传播进行无线通信,识别距离较远,且标签与阅读器之间可以有障碍物遮挡,进而实现非视距(Non Line of Sight)检测。而条形码和智能卡必须准确的放置于指定位置,无法实现自动化识别。条形码的读取距离也非常短,且之间不能有任何遮挡;智能卡则需要卡片和读写器之间有直接的接触。此外,RFID阅读器在一定范围内可以快速的识别多个标签,而条形码和智能卡只能一对一读取。
这些突出的优势使RFID在物联网领域有着极大的应用潜能。但至今仍需要克服的是其标签的成本过高,无法大规模应用的问题。因此,去掉集成电路(IC)芯片,研制出低成本的无芯片RFID标签成为当前RFID技术研究的热点领域。
目前,频域无芯片RFID标签的设计中,双极化标签因其可实现大容量而受到重视。但大多数设计都存在标签与阅读器之间因对准角度变化而出现极化失配的问题,该缺陷使得标签与阅读器必须正对放置,难以适应实际标签位置复杂多变的环境要求。
发明内容
为了克服现有技术存在的缺点与不足,本发明提供一种基于角度定位的全向无芯片RFID标签。
本发明采用如下技术方案:
一种基于角度定位的全向无芯片RFID标签,其特征在于,包括天线辐射贴片结构及介质基板结构,所述天线辐射贴片结构位于介质基板结构的上表面,所述天线辐射贴片结构由矩形贴片构成,所述矩形贴片印制有上方编码单元及下方定位单元,所述下方定位单元位于上方编码单元的正下方。
所述上方编码单元由箭头形开槽缝隙构成,所述箭头形开槽缝隙关于矩形贴片的中心点对称。
所述上方编码单元由四组结构相同的箭头形开槽缝隙构成,分别位于矩形贴片的四个角,其中两组沿着主对角线开槽,另外两组沿着副对角线开槽,分别关于矩形贴片的中心点对称。
每组箭头形开槽缝隙由四个箭头形开槽缝隙构成,箭头形开槽缝隙包括水平臂、垂直臂及45度U型弯折臂,所述45度U型弯折臂的底朝向矩形贴片的中心点,水平臂和垂直臂分别与45度U型弯折臂连接。
所述四个箭头形开槽缝隙沿着对角线由中心点到边缘的长度逐渐递减。
所述下方定位单元由矩形细槽构成。
所述矩形细槽实现角度定位,具体如下:
利用反向散射电场在水平和垂直方向上两个分量的比值,确定标签上矩形细槽与水平极化波方向间的夹角α,从而知道标签此时的失配角度。
当沿z轴方向发射的x轴方向水平极化入射波照射到该矩形细槽上时,当矩形细槽与入射波电场方向间的夹角为α时,在谐振频率上,反向散射电场在水平方向上的分量Esx和垂直方向上的分量Esy分别如式(1),(2)所示,其中k为比例系数,Ei为入射电场强度。
Esx=k×Ei×cosα×sinα  (1)
Esy=k×Ei×cosα×cosα  (2)
散射电场的水平分量Esx正比于cosα×cosα,垂直分量Esy正比于cosα×sinα。这两个分量的比值:
Esx/Esy=tanα  (3)
因此,根据反向散射电场在水平和垂直方向上两个分量的比值,就确定标签上矩形细槽与水平极化波方向间的夹角α,从而知道标签此时的失配角度。
将阅读区域按照标签40°阅读阈值进行划分,该标签可实现0°~360°区域的全向阅读。
本发明的有益效果:
(1)本发明具有小型化、低成本、大容量的特点;
(2)本发明提出了将角度传感器应用于标签的角度定位之中,利用矩形细槽反射的回波Ex和Ey分量之比,可得到标签所失配的角度。再根据阅读器可识别的角度范围,通过阅读器角度区域的划分,设置不同角度的阅读器从而实现双极化标签全向的特性,改变了双极化标签对角度敏感的现状;
(3)该角度定位技术可应用于任意双极化标签,具有普适意义。
附图说明
图1是本发明一种基于角度定位的全向双极化RFID标签天线的俯视图;
图2是本发明一种基于角度定位的全向双极化RFID标签天线的侧视图;
图3是本发明一种基于角度定位的全向双极化RFID标签天线的参数图;
图4(a)是本发明一种基于角度定位的全向双极化RFID标签天线旋转10°时散射电场Esy和Esx仿真曲线;
图4(b)是本发明一种基于角度定位的全向双极化RFID标签天线旋转160°时散射电场Esy和Esx仿真曲线;
图5是本发明一种基于角度定位的全向双极化RFID标签天线角度从0°旋转至90°时的RCS主极化和交叉极化的幅值仿真曲线;
图6是本发明一种基于角度定位的全向双极化RFID标签天线将阅读区域按照40°阈值进行划分概念图。
具体实施方式
下面结合实施例及附图,对本发明作进一步地详细说明,但本发明的实施方式不限于此。
实施例
如图1及图2所示,一种基于角度定位的全向无芯片RFID标签,所述该标签为对称结构,包括天线辐射贴片结构2及介质基板结构1,所述天线辐射贴片结构位于介质基板结构的上表面,所述天线辐射贴片结构由矩形贴片构成,所述矩形贴片印制有上方编码单元3及下方定位单元4,所述下方定位单元位于上方编码单元的正下方。
所述上方编码单元由四组结构尺寸相同的箭头形开槽缝隙构成,四组分别沿着主、副对角线开槽对称。相邻两组箭头形开槽缝隙相隔一定距离,四组分别位于矩形贴片的四个角,其中两组沿着主对角线开槽,另外两组沿着副对角线开槽,四组箭头形开槽缝隙关于矩形贴片的中心点对称。
本实施例中,每组箭头形开槽缝隙由四个箭头形开槽缝隙构成,所述四个箭头形开槽缝隙相隔一定距离,箭头形开槽缝隙包括水平臂、垂直壁及45度U型弯折臂,所述45度弯折臂的开口朝向矩形贴片的边缘,底朝向中心点,45度弯折臂开在对角线上,每个箭头形开槽缝隙的水平臂及垂直壁相等,且与45度弯折臂连接,所述四个箭头形开槽缝隙沿着对角线由中心点到边缘的长度逐渐递减。
所述四组箭头形开槽缝隙的垂直臂及水平臂分别构成四个矩形。
本实施例中具体尺寸如图3所示,具体的参数为辐射贴片水平边长L=16mm,垂直边长W=17mm,箭头形开槽结构的水平和垂直臂长相同,为L1=6.45mm、L2=5.32mm、L3=3.98mm及L4=2.35mm。所述斜45度U型弯折臂长边依次为S1=1.2mm、S2=1.5mm、S3=1.9mm及S4=2.6mm,短边为W1=0.5mm。所述最外边缝隙与贴片相隔W2=0.42mm,所述主、副对角线缝隙相隔W3=0.55mm。所述矩形细槽长La=14.6mm,宽Wa=0.2mm,其谐振在7GHz附近。所述主对角线极化方向坐标系为MD,所述副对角线极化方向坐标系为VD。
所述下方定位单元由矩形细槽构成,所述矩形细槽距上方编码单元0.72mm,所述矩形细槽长14.6mm,宽0.2mm。
当沿z轴方向发射的x轴方向水平极化入射波照射到该矩形细槽上时,当矩形细槽与入射波电场方向间的夹角为α时,在谐振频率上,反向散射电场在水平方向上的分量Esx和垂直方向上的分量Esy分别如式(1),(2)所示,其中k为比例系数,Ei为入射电场强度。
Esx=k×Ei×cosα×sinα  (1)
Esy=k×Ei×cosα×cosα  (2)
可以看出,散射电场的水平分量Esx正比于cosα×cosα,垂直分量Esy正比于cosα×sinα。这两个分量的比值:
Esx/Esy=tanα  (3)
因此,根据反向散射电场在水平和垂直方向上两个分量的比值,就可以确定标签上矩形细槽与水平极化波方向间的夹角α,从而知道标签此时的失配角度。
本实施例中,所述介质基板采用Taconic TLX-8,其相对介电常数为2.55,电损耗角正切为0.0019,介质基板水平边长为16mm,垂直边长为17mm,厚度H为0.5mm。所述天线辐射贴片单元为矩形,水平边长为15mm,垂直边长为16mm。
所述天线辐射单元采用双极化激励,所述双极化激励为相互正交的主、副对角线极化方向上的线性极化平面电磁波。
如图4(a)所示,标签旋转10°时散射电场Esy和Esx仿真结果。可见,在固定频率7.14GHz时,Esx(dB)=-52.18dB、Esy(dB)=-58.38dB。计算可得角度α=13.49°,误差为3.49°,在可接受范围内。
如图4(b)所示,标签旋转160°时散射电场Esy和Esx仿真结果。可见,在固定频率7GHz时,Esx(dB)=-46.85dB、Esy(dB)=-53.67dB。计算可得角度α=168.25°,误差为8.25°,在可接受范围内。
如图5所示,标签的角度旋转0至90°时,其RCS主极化和交叉极化的幅值仿真结果,可见当标签旋转至40°时,该标签的主极化幅值仍大于阅读器可检测到的陷波最小分辨率3dB,可以被检测到;交叉极化幅值低于3dB,无法被检测到,从而不会对主极化产生干扰。因此该标签失配角度低于40°时可正常工作。
如图6所示,根据标签可旋转的40°阈值和定位技术,可将阅读区域进行划分,从图中可见只需3个阅读器就可实现0°~180°范围的阅读,由于标签是中心对称结构,因此180°~360°与0°~180°相同,从而实现整个360°区域的全向阅读。
通过角度定位和阅读区域的划分,使得该标签天线克服了其它双极化标签无法实现的全向阅读的缺点,使得双极化标签更具有实用意义。
上述实施例为本发明较佳的实施方式,但本发明的实施方式并不受所述实施例的限制,其他的任何未背离本发明的精神实质与原理下所作的改变、修饰、替代、组合、简化,均应为等效的置换方式,都包含在本发明的保护范围之内。

Claims (4)

1.一种基于角度定位的全向无芯片RFID标签,其特征在于,包括天线辐射贴片结构及介质基板结构,所述天线辐射贴片结构位于介质基板结构的上表面,所述天线辐射贴片结构由矩形贴片构成,所述矩形贴片印制有上方编码单元及下方定位单元,所述下方定位单元位于上方编码单元的正下方;
所述上方编码单元由箭头形开槽缝隙构成,所述箭头形开槽缝隙关于矩形贴片的中心点对称;
所述上方编码单元由四组结构相同的箭头形开槽缝隙构成,分别位于矩形贴片的四个角,其中两组沿着主对角线开槽,另外两组沿着副对角线开槽,分别关于矩形贴片的中心点对称;
所述下方定位单元由矩形细槽构成;
所述矩形细槽实现角度定位,具体如下:
利用反向散射电场在水平和垂直方向上两个分量的比值,确定标签上矩形细槽与水平极化波方向间的夹角α,从而知道标签此时的失配角度;
当沿z轴方向发射的x轴方向水平极化入射波照射到该矩形细槽上时,当矩形细槽与入射波电场方向间的夹角为α时,在谐振频率上,反向散射电场在水平方向上的分量Esx和垂直方向上的分量Esy分别如式(1),(2)所示,其中k为比例系数,Ei为入射电场强度;
Esx=k×Ei×cosα×sinα        (1)
Esy=k×Ei×cosα×cosα       (2)
散射电场的水平分量Esx正比于cosα×cosα,垂直分量Esy正比于cosα×sinα;这两个分量的比值:
Esx/Esy=tanα         (3)
根据反向散射电场在水平和垂直方向上两个分量的比值,就确定标签上矩形细槽与水平极化波方向间的夹角α,从而知道标签此时的失配角度。
2.根据权利要求1所述的全向无芯片RFID标签,其特征在于,每组箭头形开槽缝隙由四个箭头形开槽缝隙构成,箭头形开槽缝隙包括水平臂、垂直臂及45度U型弯折臂,所述45度U型弯折臂的底朝向矩形贴片的中心点,水平臂和垂直臂分别与45度U型弯折臂连接。
3.根据权利要求2所述的全向无芯片RFID标签,其特征在于,所述四个箭头形开槽缝隙沿着对角线由中心点到边缘的长度逐渐递减。
4.根据权利要求1所述的全向无芯片RFID标签,其特征在于,将阅读区域按照标签40°阅读阈值进行划分,该标签可实现0°~360°区域的全向阅读。
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