RFID 或射频识别(Radio-Frequency Identification)技术无处不在。员工身份证(Employee ID)，您在商店购买的物品上，甚至在我们的宠物内。这是一项简单而巧妙的技术，在一切都越来越数字化的世界中逐渐形成了自己的特色。对于自二战(World War II)以来一直在使用的技术而言，这令人印象深刻(Quite)。
这使得这是一个让您熟悉RFID是什么以及它今天的各种用途的好时机。
RFID的物理组件(The Physical Components Of RFID)
RFID系统由两个主要组件组成。(RFID)首先(First)，您拥有RFID标签本身。这包含 ID 信息，通常参考大型外部数据库。其次，我们有RFID阅读器。这是提取存储在RFID标签中的信息的设备。
由于这项技术使用无线电波来发送和接收信息，因此标签和阅读器都需要某种形式的天线才能工作。
RFID标签由集成电路和天线组成。换句话说，是一种内部装有电子元件的微芯片。集成电路连接到一个微型天线。这些组件对所有RFID标签都是通用的，但它们的尺寸、形状和外观差异很大。取决于它们的用途。
例如，用于开门的员工 ID 卡将RFID置于塑料片之间。当插入生物体内时，RFID芯片位于生物中性玻璃胶囊内。仅举两个方法。
RFID芯片内部的数据(The Data Inside RFID Chips)
RFID标签的存储空间非常小。大多数标签只有足够的空间容纳 96 位。尽管多达 2000 位是可能的。
考虑到扩展的ASCII字符集每个字符使用 8 位，并且没有太多空间。有了可用空间，就可以存储姓名或电话号码之类的东西。然而，存储在RFID(RFID)芯片中的数据引用外部数据库中的记录更为常见。
RFID芯片还具有在可读性和可写性方面变化的存储器。大多数RFID芯片可能是只读类型的。无法立即更改数据的地方。由于RFID的存储编号可以链接到任何数据库条目，因此这是使用大量RFID标签的一种流行且具有成本效益的方式。这也有助于序列号是唯一的并且不能被篡改。这是您可以在药瓶和其他批量生产的产品上找到的那种标签。
还有一次性写入卡，也称为“现场可编程” RFID芯片。这些芯片可以将数据写入一次，但从那时起它们只能被读取。这些对于小型应用程序很有用。然后你有读写标签，可以根据需要覆盖。
什么是有源和无源 RFID 标签？(What Are Active vs Passive RFID Tags?)
RFID标签有两种主要变体。大多数人遇到的是被动的。它没有自己的电源。相反，它通过天线从RFID阅读器获取能量，用于释放其微小的数据缓存。(RFID)
无源RFID标签的优点很多。由于不需要维护或供电，它们可以永久嵌入物体中。这使得保护它们免受伤害或隐藏它们变得容易。
缺点是无源标签的范围比有源标签短。它们有一个内部电源，可以让他们不断地或以设定的时间间隔广播他们的信号。RFID技术使用的电力非常少，因此即使是有源设备也可以运行很长时间，而无需充电或更换新电池。
射频识别频率(RFID Frequencies)
RFID标签在许多不同的频带中运行：
- 低频：30 Khz – 500 Khz。这些标签的范围很短，通常只有几英寸。
- 高频：3MHz – 30MHz。这些标签的范围从英寸到英尺。
- 超高频：300Mhz – 960 MHz。平均 25 英尺的射程。
- 微波频率(Microwave Frequency)：2.45GHz，范围超过 30 英尺。
无源标签通常是低频或高频(Frequency)标签，超高频和微波(Microwave Frequency)标签需要有源功率才能工作。
RFID 和智能手机 NFC(RFID & Smartphone NFC)
许多更新、更高端的智能手机型号都具有称为“ NFC ”或近场通信(near-field communication)的功能。这是一种无线通信功能，它使用与RFID(RFID)相同的协议（本质上是语言）。
这里最大的区别在于NFC设备既可以用作RFID阅读器，也可以模拟RFID标签。这有各种各样的用途，“点击支付”非接触式移动支付就是一个很好的例子。如果两个NFC设备距离足够近可以触摸，它们也可以相互发送数据。
NFC不是通用的RFID系统。它仅在 13.56Mhz 高频RFID频段上运行，因此设计范围非常短。
射频识别屏蔽(RFID Blocking)
使用正确的材料可以阻止 RFID 信号。由于无源标签需要非常靠近阅读器才能工作，因此它们已在银行卡中使用。在许多国家，您现在可以在刷卡机上“刷卡付款”。这也导致了一种新的犯罪形式，通过钱包读取这些卡可以窃取少量金钱。
或者，RFID标签可能是使用秘密阅读器的副本。智能手机中的NFC(NFC)技术是实现这一目标的一种方式。
这就是为什么RFID 屏蔽钱包(RFID blocking wallets)现在变得流行的原因。包含RFID技术的卡片可以存放在一个特殊的袋子中，以防止在所有者不知情的情况下读取卡片。
RFID的多种用途(The Many Uses Of RFID)
RFID技术最早和最有用的用途之一是跟踪牲畜。现在它还广泛用于跟踪产品、组件和任何其他可移动物品。RFID技术可以跟踪从制造地到销售地的物品。
(RFID)如上所述，RFID用于银行卡、智能卡和各种认证系统。随着物联网 (IoT) 的兴起，它(internet of things)也成为(IoT)物理对象数字化的重要组成部分。
宠物和一些人(some humans)也被注射了RFID标签。就宠物而言，这是一种找回丢失动物的方法。在人类中，它们也可能具有医疗应用，因为一些RFID系统还可以包括传感器。
RFID或类似的东西几乎肯定会在为现实世界的物体和实体提供数字身份方面发挥重要作用。随着一切变得更加自动化，这是确保我们知道一切都在哪里以及正在发生什么的唯一真正方法。
HDG Explains : What Is RFID & What Can It Be Used For?
RFID or Radio-Frequency Identification technology is everywhere. Employee ID cards, on items you buy at a store and even inside our pets. It’s a simple yet ingenious technology that is coming into its own in a world where everything is increasingly digitized. Quite impressive for a technology that’s been in use since World War II.
Which makes this a great time to familiarise yourself with what RFID is and the various uses it’s used for today.
The Physical Components Of RFID
An RFID system consists of two main components. First, you have the RFID tag itself. This contains the ID information, usually with reference to a large external database. Secondly, we have the RFID reader. This is the device that extracts the information stored in the RFID tag.
Since this technology uses radio waves to send and receive information, both tags and readers need some form of antenna to work.
RFID tags consist of an integrated circuit and an antenna. In other words a microchip that has the electronic components inside it. The integrated circuit is connected to a tiny antenna. These components are common to all RFID tags, but they vary wildly in size, shape and appearance. Depending on what they are to be used for.
For example, employee ID cards that are used to open doors layer the RFID between sheets of plastic. When inserted into living creatures, the RFID chip sits inside a biologically neutral glass capsule. To name but two approaches.
The Data Inside RFID Chips
RFID tags have very little storage space. Most tags only have enough room for 96 bits. Although as many as 2000 bits is possible.
Consider that the extended ASCII character set uses eight bits per character, and there isn’t much room. With the available space, it’s possible to store something like a name or telephone number. However it’s far more common for the data stored inside an RFID chip to reference a record in an external database.
RFID chips also have memory that varies in terms of readability and writability. Most RFID chips are likely to be of the read-only type. Where the data cannot be changed out of the box. Since the RFID’s stored number can be linked to any database entry, this is a popular and cost effective way to use large volumes of RFID tags. It also helps that the serial numbers are unique and can’t be tampered with. This is the sort of tag you’ll find on pill bottles and other mass-produced products.
There are also write-once cards, also known as “field programmable” RFID chips. These chips can have data written to them once, but from then on they can only be read from. These are useful for small-scale applications. Then you have read-write tags, which can be overwritten as needed.
What Are Active vs Passive RFID Tags?
There are two main variants of RFID tag. The one that most people encounter is passive. It has no power source of its own. Instead, it gets energy from the RFID reader via the antenna, which it uses to disgorge its tiny cache of data.
The advantages of passive RFID tags are many. Since it requires no maintenance or power, they can be permanently embedded in objects. This makes it easy to protect them from harm or to hide them.
The downside is that passive tags have a shorter range than active tags. Which have an internal power source that allows them to broadcast their signal constantly or at set intervals. RFID technology uses very little power, so even active units can run for a significant amount of time without needing a recharge or a new battery.
RFID Frequencies
RFID tags operate in a number of different frequency bands:
- Low-frequency: 30Khz – 500 Khz. These tags have very short ranges, usually only inches.
- High-frequency: 3MHz – 30MHz. These tags range from inches to feet.
- Ultra-high Frequency: 300Mhz – 960 MHz. An average 25-foot range.
- Microwave Frequency: 2.45GHz, with ranges over 30 feet.
Passive tags are usually either Low- or High- Frequency, with the Ultra-high and Microwave Frequency tags needing active power to work.
RFID & Smartphone NFC
Many newer, higher-end models of smartphone have a feature known as “NFC” or near-field communication. This is a wireless communications feature that uses the same protocol (essentially the language) as RFID.
The big difference here is that NFC devices can be used as both an RFID reader and can simulate RFID tags. There are all sorts of uses for this, with “tap and pay” contactless mobile payments being a prime example. Two NFC devices can also send data to each other if they are close enough to touch.
NFC is not a universal RFID system. It only operated on the 13.56Mhz high-frequency RFID band, making it very short range by design.
RFID Blocking
RFID signals can be blocked using the right materials. Since passive tags need to be pretty close to the reader to work, they’ve found use in bank cards. In many countries you can now “tap and pay” on card machines. This has also led to a new form of crime, where small amounts of money can be stolen by reading these cards through wallets.
Alternatively,the RFID tag could potentially be copies using a surreptitious reader. NFC technology in smartphones is one way this can be done.
Which is why RFID blocking wallets have now become popular. Cards that contain RFID technology can be stored in a special pouch that prevents the card being read without the owner’s knowledge.
The Many Uses Of RFID
One of the earliest and most useful uses of RFID technology was tracking livestock. Now it’s also used extensively to track products, components and any other movable items. RFID technology can track an item from where it is made to where it is sold.
RFID is, as mentioned above, used in bank cards, smart cards and various authentication systems. With the rise of the internet of things (IoT) it’s also becoming an essential part of the digitization of physical objects.
Pets and some humans are also being injected with RFID tags. In the case of pets, it’s a way to recover lost animals. In humans they may also have medical applications, since some RFID systems can also include sensors.
RFID, or something like it, is almost certain to play a major role in giving real-world objects and entities a digital identity. As everything becomes more automated, it’s the only real way to make sure we know where everything is and what’s happening to it.
