Radio Frequency Identification Sensor 

Radio-Frequency Identification (RFID) is one of the earliest sensor-based technologies that has gained renewed importance in recent years. As part of a family of automatic identification technologies, alongside barcodes and magnetic strips, RFID uses radio-frequency waves to identify and track objects. Since the 1970s, barcodes have been the standard tool in retail and logistics; however, RFID offers several advantages that have led major corporations such as Wal-Mart, Target, and Dillard’s to invest heavily in this technology to streamline supply chain operations, reduce costs, and improve sales performance. 

How RFID Works 

An RFID system consists of four main components: 

1. Tag – attached to the product or item being tracked. 
2. Interrogator (Reader) – a device that sends signals to the tag. 
3. Antennae – connected to the reader for transmitting and receiving signals. 
4. Computer System – manages the reader and captures the data. 

There are two main types of RFID tags: 

• Passive Tags: These tags have no power source of their own. They are energized by the electromagnetic field emitted by a reader and transmit information only when activated. Passive tags are lightweight, inexpensive, and currently dominate retail applications. However, they only function when within the range of a reader’s magnetic field. 

• Active Tags: These contain an onboard battery, allowing them to transmit signals independently of a reader. Active tags offer longer read ranges, higher accuracy, and more sophisticated data storage. They are commonly used in defense, transportation, and toll collection systems like EZ Pass. However, they are larger, more costly, and have limited lifespans due to battery depletion. 

Data Representation in RFID 

The most common standard for RFID data is the Electronic Product Code (EPC), considered the next generation of the Universal Product Code (UPC). Like the UPC, the EPC identifies product types and manufacturers, but it includes an additional serial number to uniquely identify each item. 

For instance, Serialized Global Trade Identification Numbers (SGTINs) are used to identify individual cases or pallets. This is a significant improvement over barcodes, which only identify product families (e.g., an 8-pack of tissue paper) but not individual cases. With RFID, companies can track each unique case, providing much greater visibility and control over supply chain operations. 

Currently, most RFID tags hold 96 bits of data, which is sufficient for serialized trade identifiers. EPCglobal, Inc., a standards organization, has developed global frameworks to regulate and standardize RFID data representation for interoperability across industries. 

Applications in Supply Chain Efficiency and Effectiveness 

The real strength of RFID lies in the massive amounts of data it generates, which can be used to improve both efficiency (doing processes faster with fewer resources) and effectiveness (doing processes better with fewer errors). 

• Efficiency Gains: 

Instead of manually scanning barcodes, RFID tags can be read automatically at warehouse entry points. For example, Gillette reduced pallet-receiving times from 20 seconds to 5 seconds using RFID. The physical unloading process remained unchanged, but the elimination of manual scanning created significant time savings. 

• Effectiveness Improvements: 

Wal-Mart experienced a 21% reduction in stock-outs through RFID-enabled inventory tracking. RFID data helped generate more accurate replenishment lists, ensuring that shelves were restocked more effectively without altering the replenishment process itself. 

• Inventory Accuracy: 

RFID also reduces human errors in stock management, leading to better forecasting, replenishment, and reduced operational costs. 

RFID for Perishable Goods Management 

Perishable products pose unique challenges in supply chain management due to their limited shelf lives, sensitivity to environmental conditions, and high volume of goods transported over long distances. Examples include food, pharmaceuticals, cosmetics, flowers, and auto parts. Even minor spoilage can result in significant financial losses. 

RFID-enabled sensors, particularly those measuring temperature, have proven invaluable in maintaining product quality and safety across the supply chain. Unlike traditional systems that only provide temperature readings at specific checkpoints (e.g., during loading and delivery), RFID sensors can continuously monitor environmental conditions in real time. 

RFID-Enabled Environmental Monitoring 

Studies on RFID in refrigerated trucks show that temperatures vary greatly depending on pallet position (top, middle, or bottom), load configuration, container type, and packaging material. Without RFID, companies could only make single-point measurements, such as at the time of loading and delivery. This limited visibility masked critical variations that could compromise product quality. 

RFID-based continuous monitoring allows businesses to detect and respond to environmental changes throughout the supply chain journey. These insights help maintain safety standards, improve product quality, and enhance decision-making. For example, real-time alerts can trigger corrective actions when temperature thresholds are exceeded. 

References:  

Schwalbe, K. (2019). Information technology project management (9th ed.). Cengage.