Wave Hello To Radio Frequency Identification

You leave the buzzing store on a Saturday morning. As you are skipping out of the store, you begin to hear a harsh ringing. The security alarm is going off. You awkwardly turn to the employees of the store knowing you did not steal the avocado-oil-almond extract-rose-petal-bath bomb thing the Lush employee really wanted you to buy. It was just a glitch in the system. But what caused this startling, head-turning situation to emerge? It was the workings of Radio Frequency Identification Technology.

What Is Radio Frequency Identification?

Radio Frequency Technology or RFID, is used to track tags on objects. It uses electromagnetic waves to continually emit radio waves which are what detect the object with the RFID tag on it. Once it is detected, the RFID tag transmits to the reader the specific feedback. Unlike the technology used in barcodes, it does not require to be in the line of sight of the tag to detect it. This is why it can discover hidden objects in bags.

From This Video
  1. Active tags: Contain their own power source and have a reading range of 100 meters.
  2. Passive tags: Depend on the radio emitted from the RFID reader for their energy source because they do not have their own power supplies. It has a reading range of 25 meters.
  3. Semi-passive tags: Contain a power supply of their own, but its communication is confined to backscatter. It has a longer reading range than passive tags.

Backscatter ~ When an RFID contains no battery and sends a reply back to the reader using the same energy that it received from the reader’s transmission.

From This Video
  • Microcontroller: Analyzes the data received from the RFID tag. It governs and processes the functions of the system.
  • Signal Generator: Generates the radio waves transmitted using the antenna.
  • Signal Detecter: Accepts the feedback signals from the RFID tag.
From This Video
  • Transponder: Because passive tags do not have their own power supply, the transponders' job is to collect radio waves from the reader and send the feedback signal back to the reader.
  • Rectifier Circuit: Allows radio waves to be held over the capacitator.
  • Controller: The energy used from the rectifier circuit is harnessed for the use of the controller and the memory element.

Near-Field Coupling:

Near field coupling operates at a frequency of 125 kHz (kilohertz) to 13.56 MHz (megahertz) and at a range of 10cm to 1m. Once the RFID reader generates a field, which gets coupled (integrated) with the antenna of the tag, a voltage is created. The switching of the load on and off also creates voltage through the RFID reader. This is known as Load Modulation.

Now, assume we will turn the switch on and off according to the specific data stored in the tag. The RFID reader can read this data in the form of voltage across the reader coil and determine the function that takes place (ex. alarm going off)… WOAH

I like to think of it as if you are switching two hoses facing each other are on. Each time you switch them both on, their opposing flows of water against each other will create a mist in the air from the strongly opposing flows (voltage), and each time you turn them off, there is still mist in the air (voltage).

Far-Field Coupling:

From This Video

Far-field coupling operates at a frequency of 860–960 MHz. The RFID reader is constantly emitting towards the tag radio waves of a specific frequency. A weak response signal is then sent back to the RFID reader (backscattered signal). The voltage of this signal is dependant on the load across the coil. If the loads are the same, the strength (voltage) of the backscattered signal will be higher. If not, the strength will be less. It is in this way that changes to the load can be applied.

Changes to the load in accordance with the data being held opposite to this RFID tag is sent back to the reader to be processed.

  • RFID readers can often face collision problems when multiple signals overlap. This is what happened in the common example stated in the introduction.
  • Many speculate that one day RFID trackers could be used for the worse… unlawful tracking. But I believe this is avoidable through thorough regulation and transparency with each step in creating protocols for its use when the day does come.


Security actually isn’t the only use of RFID technology. It can also be used for revolutionizing industries such as food shopping and agriculture.

Amazon Go, San Fransisco, California

At Amazon Go, Radio Frequency Identification in being used on items and is connected to customers using the Amazon Go application. Each item has an RFID tag on it and once you leave the store, you are billed through the application.

In countries like Kenya, many make their livelihood off of agriculture and thus the stealing of cattle (cattle raids) has vast impacts on local infrastructures. The initiative supported and overseen by the Kenyan government strives to implement this technology into as many cattle farms as possible.

The Bolus (RFID tag) is either applied to the cows’ ear tag or implanted into the reticulum of the animal. The data from the animal allows their location to be monitored and tracked through livestock management system software. This technology of smart labels is growing exponentially and is expected to be worth $10 billion by the end of 2020.

  • Radio Frequency Identification is the communication using electromagnetic coupling in the radio frequency part of the electromagnetic spectrum. Wirelessly, objects, and living beings can be tracked.
  • There are many specific parts of the reader and the tag each with their own function
  • There are several downsides, but its positive impacts around the globe outway them as the technology continues to grow immensely

Radio Frequency Identification technology is much more than a wireless communication technique, it is changing the way we work and live our everyday lives. Whether it is agricultural, or financial, it is shifting our perspective on how data can be transported.

17-year-old Innovator at The Knowledge Society