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80个基本K线组合形态图解

Di_Shi_Zhang_Wei_Bo_RFIDJi_Zhu_.ppt - 微波 RFID 技术 主要内容 9.1.

9.1 微波 80个基本K线组合形态图解 RFID 关键技术  与 HF 、低频 RFID 技术的比较  RFID 技术中微波频段通常所用频率是 433 MHz , 860~960 MHz , 2.45 GHz , 5.8 GHz  工作距离:具有较远的读写距离,通常为大于 1 m  耦合方式:多采用反向散射方式而不是电感耦合方 式  天线:尺寸较小  防碰撞:必须有较快、有效的处理碰撞的能力  应答器功能:还可集成有传感器,例如温度传感器 、应力传感器等

9.1 微波 RFID 关键技术  可靠、低功耗的应答器芯片电路设计  电源恢复电路、电源稳压电路、反向散射调制电路 、时钟提取 /产生电路、控制单元、存储器等。  电源恢复电路: 最大限度地提取并利用 所接收的 电 磁信号的能量 ;还涉及到天线阻抗与芯片阻抗的 匹 配 网络的设计。  电源稳压电路:输入信号功率可以变化几百甚至几 千倍,必须设计可靠地电源 稳压 电路,为芯片提供 全局电源。  80个基本K线组合形态图解 反向散射调制电路:通过改变阻抗调制载波,向读 写器发送上行信号。

9.1 微波 RFID 关键技术  天线设计技术  设计目标 :传输最大的能量进出应答器芯片;需要仔 细的设计,以实现天线和信号传播环境、芯片电路的 匹配  信号空间传播模型 :受到应用环境影响很大,而且读 写器与应答器之间可能还有相对运动;  与输入阻抗的匹配 :超高频芯片电路的输入阻抗与输 入信号频率、功率有关,不同的应用环境,输入阻抗 不同,难以模拟;  天线的设计 :受到所标识物体的形状及物理特性的影 响,如贴标签物体的介电常数、金属表面的反射等;  MIMO 技术 :读写器通常采用多副天线提高抗干扰能 力和读写速度;

9.2 天线技术  天线的定义 天线是一种用金属导线、金属面或者其他材料构成一定形状, 架设在一定空间,以电磁波形式发射或接收射频信号的装置。 在 RFID 系统中,以读 写器向标签传送数据为例, 由读写器(发射机)产生高 频震荡能量,经过传输线传 送到发射天线,然后以电磁 波形式向预定方向辐射。接 收天线则将接收到的电磁波 能量通过馈线送到标签(接 收机),完成无线电波传输 的过程。

9.2.1 天线技术概述  天线的种类 ( 1 )按照 工作性质 分类:发射天线、接收天线和收发共用天线。 ( 2 )按照 波段 分类: 长 波天线、中波天线、 80个基本K线组合形态图解 短 波天线、超 短 波天 线和微波天线等。 ( 3 )按照 结 构 分类:线状天线、面状天线、 缝隙 天线和微 80个基本K线组合形态图解 带 天线 等。 ( 4 )按照 用 途 分类: 广 播天线、通信天线、 雷达 天线、导 航 天线 和 RFID 天线等。

9.2.1 天线技术概述  各 种天线 都 可以分 80个基本K线组合形态图解 割 为无限多 个 基本 元 , 即 基本振子 , 这些基本 元上载有 交 变电 流 或 交 变磁 流 , 每 一 个基本 元上的电磁 流 的 振幅 、相 位 和方向 均假 设是相同的。天线可以 看 成是由 这些基本 元按 一定的 结 构形式 连 接而成的。 80个基本K线组合形态图解  基本 元是一种 基本 的辐射单元, 根 据 基本 元的辐射特性,按电磁 场 的 叠加原 理 80个基本K线组合形态图解 即 可 得 出 各 类天线的辐射特性。  基本 元的类型可以分为 三 类:  第 一类是 电 流 元 ,载有 交 变电 流 , 又称 为 电 基本振子 80个基本K线组合形态图解 ;  第二 类为 磁 流 元 ,载有 交 变磁 流 , 又称 为 磁 基本振子 ,磁 基本振子 的辐射 场 可 从 电 基本振子 的辐射 场 对 偶得 出;  第三 类为 面 基本 元 ,面 基本 元是构成面天线的 基本 单元, 依 据等效 原 理可将 面元上的磁 场 与电 场 分别用 等效电 流 元 和 等效磁 流 元 来代 替 , 从 而利用电 基本振子 和磁 基本振子 的 结果得 80个基本K线组合形态图解 80个基本K线组合形态图解 出面 基本 元的特性 。 RFID 天线主要由电 基本振子 和磁 基本振子 构成。

9.2.2 基本振子 的辐射  电 基本振子 的辐射 电 基本振子也称 为电 偶极子 ,是为分 析 天线而 抽象 出 来 的天线 最小构成单元。如 图 所 示 为一 个 电 基本振子 。 该 电 基本振子 在 球坐 标 原 点沿 z 轴放 置,是一段 长 度 l 远小于波 长 λ 的细 短 导线。导 线上所有 点 的电 流振幅 和相 位均 被认 为是 恒 定的, 即 电 流 是等 幅 同相分 布 。

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The company el puerto de liverpool recently celebrated 170 years with annual. Revenues of more than 100 billion pesos, 85 warehouses and a presence in 59 cities, and as part of its celebration. The company had the idea of ​​offering experiences, exhibitions, within and outside stores. As well as exhibitions of its iconic bags intervened by mexican artists, according to el universal. The company el puerto de liverpool recently celebrated 170 years with annual revenues of more than 100 billion pesos. 85 stores and a presence in 59 cities, and as part of its celebration. The company had the idea of ​​offering experiential marketing , exhibitions , inside and outside stores. As well as exhibitions of its iconic bags intervened by mexican artists. According to el universal. However, the store’s iconic bags were large and are place on avenues in the polanco area of 80个基本K线组合形态图解 ​​mexico city.

Who Claimed That Outdoor Advertising Obstructed Pedestrian

paths and therefore. Therefore they made a “Citizen closure” , arguing that they were recovering the public space. The “citizen closure” was accompanied by strong criticism under the twitter hashtag #liverpoolgandalla. Which according to tweetreach, achieved. More than 292 thousand impressions in a couple of hours, reaching at times 100 tweets per minute. While 34 percent of the cyber protest were tweets with opinions and 61 percent, rts. Hours later, liverpool 80个基本K线组合形态图解 issued its position on the matter, arguing that. It had all the permits and requirements. But that The Ghana WhatsApp Number List neighbors did not like them”. Although personnel from the miguel hidalgo delegation removed the intervened bags from avenida horacio, in polanco. According to twitter complaints from residents of polanco.

an art exhibition. But apparently it was never

Ghana WhatsApp Number List

handled as advertising for liverpool. Which caused discontent, 80个基本K线组合形态图解 and they even pointed it out as “ advertising disguised as art. Liverpoolgandalla you need to read the outdoor advertising law article 13 sections I. Any outdoor advertisement must have a plate with the name or denomination of the owner. Permit number, license or temporary authorization, validity, regardless of the brand. In addition to each advertisement it must be positioned at a certain distance from another. In addition to the fact that word ads are only authorized to be installed in gas station.

Start Blogging Link Building for Ecommerce Store

The company el puerto de liverpool recently celebrated 170 years with annual. Revenues of more than 100 billion pesos, 85 warehouses and a presence in 59 cities, and as part of its celebration. The company had the idea of ​​offering experiences, exhibitions, within and outside stores. As well as exhibitions of its iconic bags intervened by mexican artists, according to el universal. The company el puerto de liverpool recently celebrated 170 years with annual revenues of more than 100 billion pesos. 85 80个基本K线组合形态图解 stores and a presence in 59 cities, and as part of its celebration. The company had the idea of ​​offering experiential marketing , exhibitions , inside and outside stores. As well as exhibitions of its iconic bags intervened by mexican artists. According to el universal. However, the store’s iconic bags were large and are place on avenues in the polanco area of ​​mexico city.

Who Claimed That Outdoor Advertising Obstructed Pedestrian

paths and therefore. Therefore they made a “Citizen closure” , arguing that they were recovering the public space. The “citizen closure” was accompanied by strong 80个基本K线组合形态图解 criticism under the twitter hashtag #liverpoolgandalla. Which according to tweetreach, achieved. More than 80个基本K线组合形态图解 292 thousand impressions in a couple of hours, reaching at times 100 tweets per minute. While 34 percent of the cyber protest were tweets with opinions and 80个基本K线组合形态图解 80个基本K线组合形态图解 61 percent, rts. Hours later, liverpool issued its position on the matter, arguing that. It had all the permits and requirements. But that The Ghana WhatsApp Number List neighbors did not like them”. Although personnel from the miguel hidalgo delegation removed the intervened bags from avenida horacio, in polanco. According to twitter complaints from residents of polanco.

an art exhibition. But apparently it was never

Ghana WhatsApp Number List

handled 80个基本K线组合形态图解 as advertising for liverpool. Which caused discontent, and they even pointed it out as “ advertising disguised as art. Liverpoolgandalla you need to read the outdoor advertising law article 13 sections I. Any outdoor advertisement must have a plate with the 80个基本K线组合形态图解 name or denomination of the owner. Permit number, license or temporary authorization, validity, regardless of the brand. In addition to each advertisement it must be positioned at a certain distance from another. In addition to the fact that word ads are only authorized to be installed in gas station.

Translation of "medicine stove" in Chinese

What the founder of our clan left us. besides his extraordinary 80个基本K线组合形态图解 skills, was this medicine stove I can't believe under my charge.

She learned about the competition on TV and is worried that I will be beaten up I'm sorry, it was my turn to wash the medicine stove I was going to do it

Other results

Twenty saints and 40 volunteers reached the site within hours of the cyclone, with 10 tons of food grains, two truckloads of millet, 500 primus stoves, 600 sets of steel utensils, two trucks of clothes, 200 cartons of specialized clothes and shoes, medicines worth Rs 250,000

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