当前位置:首页 >> 文学研究 >>

CST


CST STUDIO SUITE? 2006B Application Note

RFID Simulation
Overview Operating Principles Inductive Coupling Microwave Coupling Matching of RFID Tags Summary
1 twi / v1.0 / 09. Nov 2006 www.cst.com

Overview
Radio Frequency IDentification
? Fundamental tool for Automatic Identification:
authentication, ticketing, access control, supply management, parking, payment, vending, surveillance

? Advantages:
– – – –
2

Contains more information than e.g. Barcodes Can be read/write Contactless ID (in contrast to phone or bank cards) May become cheap mass product (e.g. in supermarkets)
www.cst.com

General Principle
Data

Reader
Energy

RFID tag

Typical characteristics of RFID: ? ? ? ? ?
3

Tag is a passive device, energy is transmitted from reader Distance mm to 10m (typically ~20 cm) Contains silicon chip, can be read only or read/write Responds with modulated signal Mostly printed (planar) structures
www.cst.com

Frequencies
125/134 kHz Animal identification, industrial applications, very robust, low data transmisstion (64 bit) Electronic Article Surveillance (EAS) "Smart Labels" widely used for product/article ID Several applications Vehicle identification, electronic toll collection electronic toll collection in Europe
www.cst.com

7.4 - 8.8 MHz 13.56 MHz 868 - 928 MHz 2.4 GHz 5.8 GHz
4

Operating Principles
? Inductive Coupling (125 kHz – 15 MHz)
– Very small dimensions compared to λ – Coupling only through magnetic field – Tag typically a planar coil

? Microwave Coupling (868 MHz – 5.8 GHz)
– typically a regular antenna (e.g. planar folded dipole) – Matching network important to keep antenna small
5 www.cst.com

Inductive Coupling
RFID tags are mostly planar coils with small dimensions compared to λ Hexahedral or tetrahedral F-Solver are typically most suited. Example for 13.56 MHz
At 13.56 MHz Measurement: (7.15 + 398i) Ω Simulation: (7.0 + 334i) Ω

Measurement CST MWS simulation

Imaginary part of impedance

Curves are overlying each other, excellent agreement!

6
with courtesy and permission of Legic Identsystems AG

www.cst.com

Microwave Coupling
900 MHz RFID Tag Antenna
Simulation of the planar structure with a standard 50 Ω port
www.alientechnology.com/products/rfid_tags.php

Mesh view
7 www.cst.com

900 MHz RFID Tag Antenna
50 Ω

Wrong resonance frequency, low coupling Antenna is poorly matched
8

Non-resonant simulation, 3 min sim. time

www.cst.com

Matching Procedure

Matching impedance: 1.55 Ω
Lumped Capacitance for shifting the resonance frequency: Z_im = 89.5i Ω L = 15.8 nH

(or: L from ?Template Based Postprocessing“)

C=

1 Lω
2

= 1.96 pF

(or: Macros -> Calculate -> Calculate L-C-fres)
9 www.cst.com

Matching in CST DESIGN STUDIO?

1.5 Ω

Simulation run in CST DESIGN STUDIOTM: 5 sec.

Resonance frequency correct (900 MHz), excellent matching (-30 dB)

10

www.cst.com

Alternative Approach
Inclusion of lumped element in CST MWS simulation
1.5 Ω 1.96 pF

Excellent agreement between matching in Design Studio and matching in CST MWS CST DS approach is 7 times faster
11

Resonant simulation, 20 min sim. time

www.cst.com

Field Monitors
With lumped element included in CST MWS all field monitors are available
Current Density

Electric Field

Farfield Dipole field
12 www.cst.com

Test under Realistic Surroundings

RFID tag in front of metal can
13

RFID tag in front of water bottles
www.cst.com

Field Distortion by PEC-Cans

Unsymmetric fields

Second resonance

14

poorer matching

www.cst.com

Summary
? RFID is a general concept using different technical principals ? CST complete technology approach offers best solution for each case
– Frequency Domain / CST EMS for coil type – Transient Simulator for microwave type

? Tags often contain lumped elements
– Possible in both CST MWS or CST DS – CST DS typically more efficient
15 www.cst.com



相关文章:
CST2012安装说明
CST2012安装说明_电脑基础知识_IT/计算机_专业资料。CST2012安装 该安装教程在 windows7/8 下可行,windows10 下失败. 1.安装 CST2012 及其补丁, 安装时可以选择...
变频器和CST比较
变频器及 CST 对比 可控起动传输装置(CST)是一个由多级齿轮减速器加上湿式离合器及液压控制组成的系统。 即通过液压来进行转动。 输入轴 行星轮齿圈 太阳轮 ...
CST学习报告_图文
CST 学习报告 第1章 CST 仿真基本流程:使用 CST 进行仿真,一般都要包括如下步骤: 1.1 选择合适的工作室:加速器领域,常应用的工作室有:微波工作室,电磁工作室...
CST入门讲义
CST入门讲义_信息与通信_工程科技_专业资料。CST入门 有用CST 入门主要内容: 软件介绍 软件的基本操作 微带天线仿真实例 1.1 软件介绍 CST 公司总部位于德国达姆...
cst安装步骤
执行“开始”->“所有程序”->“CST STUDIO SUITE 2013”->“CST Update Manager”, 单击 Import, 选择最新版本的 SP ,如 CST_STUDIO_SUITE_2013_...
CST仿真考题
CST仿真考题 - 基本题: 1. 要求:仿真 T 形波导,优化销钉的位置和尺寸,使频带内 S11 最小。 尺寸:T 形波导尺寸如图所示,PEC 销钉半径为 1mm 频带:9-12...
CST 的介绍
CST 的介绍_冶金/矿山/地质_工程科技_专业资料。矿山资料 CST 的介绍葆德 CST(可控启动传输)是一个二 合一齿轮箱, 组合了一个行星齿轮减速 装置和一个一体式...
CST使用教程_图文
CST使用教程_计算机软件及应用_IT/计算机_专业资料。电磁仿真软件,CST培训教程 1.1 软件介绍 CST 公司总部位于德国达姆施塔特市,成立于 1992 年。它是一 家专业...
CST STUDIO SUITE 2014激励源的概述
CST STUDIO SUITE 2014激励源的概述_电子/电路_工程科技_专业资料。CST STUDIO SUITE 2014激励源的概述Excitation Source Overview CST MICROWAVE STUDIO offers ...
24时区,GMT,UTC,DST,CST时间详解
24 时区,GMT,UTC,DST,CST 时间详解 Eric 2011-04-27 10:34:22 全球 24 个时区的划分 相较于两地时间表,可以显示世界各时区时间和地名的世界时区表(World ...
更多相关标签: