RFID is a generic term that is used to describe a system that transmits the identity of an object or person using radio waves. RFID uses an electronic device that consists of a small chip and an antenna. The chip provides a unique identifier for objects that have it, and must be scanned to retrieve information that identifies the object. RFID is designed to enable readers to capture data on tags and transmit it to a computer system.
RFID systems are grouped under the broad category of automatic identification technologies. Automatic identification technologies have been used to reduce the amount of time and labor needed to input data manually and to improve data accuracy. These technologies include bar codes, optical character readers and some biometric technologies, such as retinal scans. Unlike other Auto ID technologies RFID eliminate the need for manual scanning of tags to capture data.

How RFID Works

The RFID system consists of three components:

v     Scanning antenna- which is key to the technology.

·  The antenna puts out radio frequency signals in a relatively short range.

·  The RF radiation provides a means of communicating with the transponder tag (the RFID chip) AND (in the case of passive RFID tags) provides the RFID device with the energy to communicate.

·  The antenna receives signals back from the tag, and

·  Passes the information in digital form to a computer system.

·  The scanning antennas can be permanently affixed to a surface or be handheld.

v     Transponder – this is a radio-frequency tag programmed with information.

·  When the tag passes through the field of the scanning antenna, it detects the activation signal, and activates the RFID chip.

v     Transceiver

·  Once activated the tag transmits information on its microchip to the scanning antenna.


Majority RFID tags or transponders use silicon microchips to store unique serial numbers and any additional information. There are two broad types of RFID tags passive and active tag systems.


Active RFID tags have a transmitter and power source; usually thought not always active tags have a battery. However, active tags can also draw energy from the sun or other sources of energy.

These tags broadcast signal to transmit information stored on the microchip.

Active tags are used on large assets, like cargo containers, rail cars and bulky reusable containers that need to be tracked over long distances, because they have a read range of 60 feet to 300 feet (20 meters to 100 meters).

Active tags can generally be categorized into two:  transponders and beacons.

Active transponders are woken up when they receive a signal from a reader.

To conserve battery life, transponders only broadcast signal when within range of a reader.

They are applied in toll payment collection and checkpoint control.






Beacons are used in real-time locating systems (RTLS), to precisely locate an asset that needs to be tracked.

The beacon emits a signal with its unique identifier at pre-set intervals.

The beacon's signal is picked up by at least three reader antennas positioned around the perimeter of the area where assets are being tracked.

RTLS are usually used outside, like in distribution yards, and in large auto making manufacturing facilities to track parts bins.


Passive RFID tags basically reflect back energy coming from the reader antenna. These tags have no transmitter, power source and require no maintenance.

Passive tags operate at low frequency, high frequency or ultra-high frequency.

Radio waves perform differently at each frequency, meaning different frequencies are appropriate for different applications.

Radio waves begin to behave like light as you increase the frequency.

When they behave like light can't penetrate materials as well and they tend to bounce off many objects.  



Technical problems with RFID

Global Standards

RFID has been executed in diverse ways by different manufacturers; global standards are still being worked on. Some of these standards relate to: Automatic Identification and Data Capture Techniques, Identification Cards and related devices, Identification and communication, Agricultural electronics, Road Transport and Traffic Telematics, and Transportable Gas Cylinders - Operational Requirements - Identification of cylinders and contents

 Consumers may also have problems with RFID standards. They would have to pay to access a different company’s convenient proprietary RFID system. Alternatively, if every company had their own convenient proprietary system, a consumer would need to carry many different devices with them, in order to gain access to company systems.

System disruption

Given that RFID systems use the electromagnetic spectrum, they are somewhat easy to jam using right frequency energy. This would only bother consumers in stores due to longer waits at the checkout. However it could be devastating in other situations where RFID is progressively more used, like hospitals or in the military in the field.

Active RFID tags that use battery to increase the system range can be repetitively require maintenance due to low battery. This could result in system disruption.

Reader Collision

This kind of collision occurs when signals from two or more readers overlap. The tag is incapable of responding to simultaneous queries. Care must be taken to set up systems so as to avoid this problem; many systems use an anti-collision protocol which enables the tags to take turns in transmitting to a reader.

Tag Collision

Tag collision occurs when many tags are present in a small area; but since the read time is very fast, it is easier for vendors to develop systems that ensure that tags respond one at a time.

Security, privacy and ethics problems with RFID

The following are reported problems with RFID tags and readers.

RFID tags can be read without Consent

RFID tags can be read exclusive of being swiped or noticeably scanned just like magnetic strips or barcodes, anyone with an RFID tag reader can read the tags embedded in products without the consent of the owner of the product.
For example, Stores can scan customers’ items before they enter the store, so as to find out what they are carrying. Using this information clerks or appointed customer service assistants can suggest accessories or products associated with what customers are carrying.

RFID tags are difficult to remove

RFID tags are not easy to remove, especially for consumers; some are very small, others may be buried or implanted inside a product where consumers cannot see them. New technologies allow RFID tags to be "printed" right on a product and may not come off.

High-gain antennas enable people interested to read RFID tags even with large distances.

RFID reader/tag systems are designed to keep distance between the tag and the reader at a minimum. Nevertheless, high-gain antennas can be used to read the tags from much further away, leading to privacy problems.

RFID tags cannot differentiate between readers. RFID scanners on the other hand are very portable; in addition RFID tags can be read from a distance. This permits anyone to see the contents of anything that you carry.

RFID tags with unique serial numbers could be linked to an individual credit card number

At present, the Universal Product Code (UPC) implemented with barcodes allows each product in a store to have a unique number identifying it. With time there will be a global system of product identification that will allow all items to have unique identifiers. Once these products are scanned for purchase and paid for, the RFID tag number for a particular item can be associated with a credit card number.


Current Applications


u    Livestock Tagging

u    Wild Animal Tracking

u    Electronic Article Surveillance (EAS)

u    Automated Toll Collection

u    Animal Husbandry

u    Vehicle Anti-Theft

u    Passive / Secure Entry

u    Airline Baggage Tracking

u    Postal Package Tracking

u    Time and Attendance



Potential Applications


u    The Euro by 2005

u    Xerox PARC Page Detection

u    Department of Defense

u    Immigrations Departments

u    Hospitals


My work is adapted from the RFID Journal, AIM Global Network and