What is RFID?

Radio Frequency Identification (RFID) is the wireless non-contact use of radio frequency waves to transfer data. Tagging items with RFID tags allows users to automatically and uniquely identify and track inventory and assets. RFID takes auto-ID technology to the next level by allowing tags to be read without line of sight and, depending on the type of RFID, having a read range between a few centimeters to over 20+ meters.

RFID has come a long way from its first application of identifying airplanes as friend or foe in World War II. Not only does the technology continue to improve year over year, but the cost of implementing and using an RFID system continues to decrease, making RFID more cost-effective and efficient.

Types of RFID

Within the Electromagnetic Spectrum, there are three primary frequency ranges used for RFID transmissions – Low Frequency, High Frequency, and Ultra-High Frequency.

Low Frequency

General Frequency Range: 30 - 300 kHz
Primary Frequency Range: 125 - 134 kHz
Read Range: Contact - 10 Centimeters
Average Cost Per Tag: $0.75 - $5.00
Applications: Animal Tracking, Access Control, Car Key-Fob, Applications with High Volumes of Liquids and Metals
Pros: Works well near Liquids & Metals, Global Standards
Cons: Very Short Read Range, Limited Quantity of Memory, Low Data Transmission Rate, High Production Cost

High Frequency

Primary Frequency Range: 13.56 MHz
Read Range: Near Contact - 30 Centimeters
Average Cost Per Tag: $0.20 - $10.00
Applications: DVD Kiosks, Library Books, Personal ID Cards, Poker/Gaming Chips, NFC Applications
Pros: NFC Global Protocols, Larger Memory Options, Global Standards
Cons: Short Read Range, Low Data Transmission Rate

Ultra-High Frequency

General Frequency Range: 300 - 3000 MHz
Primary Frequency Ranges: 433 MHz, 860 - 960 MHz

There are two types of RFID that reside within the Ultra High Frequency range: Active RFID and Passive RFID.

Active RFID

Primary Frequency Range: 433 MHz, (Can use 2.45 GHz - under the Extremely High Frequency Range)
Read Range: 30 - 100+ Meters
Average Cost Per Tag: $25.00 - $50.00
Applications: Vehicle Tracking, Auto Manufacturing, Mining, Construction, Asset Tracking
Pros: Very Long Read Range, Lower Infrastructure Cost (vs. Passive RFID), Large Memory Capacity, High Data Transmission Rates
Cons: High Per Tag Cost, Shipping Restrictions (due to batteries), Complex Software may be Required, High Interference from Metal and Liquids; Few Global Standards

Passive RFID

Primary Frequency Ranges: 860 - 960 MHz
Read Range: Near Contact - 25 Meters
Average Cost Per Tag: $0.09 - $20.00
Applications: Supply Chain Tracking, Manufacturing, Pharmaceuticals, Electronic Tolling, Inventory Tracking, Race Timing, Asset Tracking
Pros: Long Read Range, Low Cost Per Tag, Wide Variety of Tag Sizes and Shapes, Global Standards, High Data Transmission Rates
Cons: High Equipment Costs, Moderate Memory Capacity, High Interference from Metal and Liquids

Applications

Race Timing
Supply Chain Management
Pharmaceutical Tracking
Inventory Tracking
IT Asset Tracking
Laundry & Textile Tracking
File Tracking
Returnable Transit Item (RTI) Tracking
Event & Attendee Tracking
Access Control
Vehicle Tracking
Tolling

Before implementing an RFID system, both Application Feasibility and Cost Feasibility should be assessed.

Application Feasibility

Application Feasibility refers to the process of determining if the application is suitable for use with RFID. Like all technology, RFID has limitations. Environmental constraints, read range limitations, and asset material composition are just a few of the different aspects that can severely impact how effective an RFID system is for a specific application. The Application Feasibility process should entail scoping of the project and the project’s environment as a starting point, and then determining if RFID (or another technology) is the right fit for the application.

Cost Feasibility

Cost Feasibility refers to assessing if implementing an RFID system is achievable from a monetary perspective. Cost Feasibility includes not just if an ROI is possible, but it also includes working with current numbers and prospective numbers to determine the estimated timeline for a return on investment. RFID systems can be expensive. They require an initial investment for testing and working with different types of equipment and tags (which may be a sunk cost for the company if the technology doesn’t pan out). After the testing phase, deployment costs begin (Read more about Fixed vs. Recurring Costs below). Only after a system has been implemented and is working properly can the timeline begin for seeing a return on the investment.

What is an RFID System

While each system will vary in terms of device types and complexity, every RFID system contains at

least the following four components:

Readers
Antennas
Tags
Cables

The simplest system can be comprised of a mobile handheld RFID reader (with an integrated antenna) and RFID tags, while more complex systems are designed using multi-port readers, GPIO boxes, additional functionality devices (e.g. stack lights), multiple antennas and cables, RFID tags, and a complete software setup.

RFID Tags

An RFID tag in its most simplistic form, is comprised of two parts – an antenna for transmitting and receiving signals, and an RFID chip (or integrated circuit, IC) which stores the tag’s ID and other information. RFID tags are affixed to items in order to track them using an RFID reader and antenna.

RFID tags transmit data about an item through radio waves to the antenna/reader combination. RFID tags typically do not have a battery (unless specified as Active or BAP tags); instead, they receive energy from the radio waves generated by the reader. When the tag receives the transmission from the reader/antenna, the energy runs through the internal antenna to the tag’s chip. The energy activates the chip, which modulates the energy with the desired information, and then transmits a signal back toward the antenna/reader.

On each chip, there are four memory banks – EPC, TID, User, and Reserved. Each of these memory banks contains information about the item that is tagged or the tag itself depending on the bank and what has been specified.

RFID Readers

An RFID reader is the brain of the RFID system and is necessary for any system to function. Readers, also called interrogators, are devices that transmit and receive radio waves in order to communicate with RFID tags. RFID readers are typically divided into two distinct types – Fixed RFID Readers and Mobile RFID Readers. Fixed readers stay in one location and are typically mounted on walls, on desks, into portals, or other stationary locations.

A common subset of fixed readers is integrated readers. An integrated RFID reader is a reader with a built-in antenna that typically includes one additional antenna port for the connection of an optional external antenna as well. Integrated readers are usually aesthetically pleasing and designed to be used for indoor applications without a high traffic of tagged items.

Mobile readers are handheld devices that allow for flexibility when reading RFID tags while still being able to communicate with a host computer or smart device. There are two primary categories of Mobile RFID readers – readers with an onboard computer, called Mobile Computing Devices, and readers that use a Bluetooth or Auxiliary connection to a smart device or tablet, called Sleds.

RFID Antenna

RFID Antennas are necessary elements in an RFID system because they convert the RFID reader’s signal into RF waves that can be picked up by RFID tags. Without some type of RFID antenna, whether integrated or standalone, the RFID reader cannot properly send and receive signals to RFID tags.

Unlike RFID readers, RFID antennas are dumb devices that receive their power directly from the reader. When the reader’s energy is transmitted to the antenna, the antenna generates an RF field and, subsequently, an RF signal is transmitted to the tags in the vicinity. The antenna’s efficiency in generating waves in a specific direction is known as the antenna’s gain

RFID Cables

RFID Antenna Cables facilitate communication between the RFID reader and RFID antenna. Without the cable, the reader cannot power and send signals to the tags via the antenna. Choosing an RFID cable may seem like an easier task than choosing other components; however, cables can vary greatly in three specific ways – connector types, length, and thickness/insulation rating – so, it is important to take all three into consideration before purchasing.

When determining the right connectors for either end of the cable, first look at the connectors on the RFID reader and the antenna. For example, if an RFID reader has an RP-TNC Female connector, one side of the cable should have an RP-TNC Male connector and vice-versa. For more information on the different types of cable connectors, check out our RFID Cable Guide.

The cable length and thickness (also called insulation rating) will vary depending on your specific solution. The length of the cable is usually determined by how far apart the RFID reader and antenna are, but it’s important to note that, the longer the cable, the more power will be lost in transit.