Radio Frequency Identification RFID is the latest technology in modern industries, driving simple tracking, automation, and security measures in the supply chain, retail, healthcare, etc. Although active RFID tags have their pros, passive RFID tags still govern the market because of their affordability and sustainability.
Instead of active tags, which use their built-in power source, passive RFID tags get their power from the radio waves transmitted by the reader. These tags are designed for various RFID systems, including the LF, HF, and UHF. The HF system, moreover, is primarily used for card payment and access control technology. At the same time, the extended read range characteristic of UHF tags makes them very prolific in logistics and retail.
Besides the basic active and passive tags, some that incorporate solar power, which are called semi-passive tags, exist. The standards set by RAIN RFID systems worldwide require proper frequency and RFID type selection to achieve efficiency. This guide unveils the various types of passive RFID tags and their most suitable uses.
What is Passive RFID Tags?
Regarding different RFID systems, passive RFID technology is a cost-effective and widely used solution. Unlike active RFID systems with an internal power supply, passive tags need energy from the reader signal to transfer data.
Passive RFID tags are more affordable than active RFID tags and are, therefore, more suitable for large-scale tracking, making the former an inexpensive and practical alternative.
Operating at RFID HF, UHF, or LF frequencies, passive tags are commonly used in various industries, including retail, logistics, and access control. Given that these tags are lightweight and cost less, they are an innovative and economical choice for the RFID projects that succeed through the balance of efficiency and cost.
Different Types of Passive RFID Tags by Frequency
Passive RFID tags are differentiated according to the frequency at which they operate, which affects their working distance, data transfer speed, and resistance to environmental factors. As opposed to active RFID systems that have their power source, passive RFID tags depend on a radio signal emitted by a reader to send data back to the reader.
The RFID system operates through three primary frequency bands, Low Frequency (LF), High Frequency (HF), and Ultra-High Frequency (UHF). Every RFID tag type has particular applications based on its range and performance. Understanding these varying RFID frequencies is crucial to picking the suitable tag type for your purposes.
1. Low Frequency (LF) RFID Tags (125–134 kHz)
The LF band operates at 125 to 134 kHz frequencies and has a short read range of only a few centimeters to about one meter. These RFID tags use a signal from a reader to power up and transmit data, so they are suitable for applications where close-range identification is only required. The LF spectrum is not considered the best for high-speed data transfer but excels in hostile environments like metal and liquid surroundings.
LF RFID is used in access control, animal tracking, and the industrial sector. Tags, for example, and smart cards are used to secure system access. Besides, in agriculture, they help keep proper track of the movements of the animals. Their common use in obstructive environments is due to their low frequency for their RFID. Hence, they are not weak from the blocked signals, making them just as reliable in difficult environments.
2. High Frequency (HF) RFID Tags (13.56 MHz)
Operating at 13.56 MHz, HF RFID tags have a moderate read range of up to one meter and are commonly used to communicate in applications that require secure data exchange. This category includes near-Field Communication (NFC) technology, which is widely used in smart cards, mobile payments, and authentication systems.
HF tag types are frequently used in various industries, including libraries, public transit systems, and medical applications. For example, hospitals use RFID to securely track medical equipment and patient records. HF is more susceptible to interference than LF RFID but provides faster data transfer. The if and HF bands are preferred for authentication and close-proximity interactions.
3. Ultra-High Frequency (UHF) RFID Tags (860–960 MHz)
RFID UHF tags operate within 860–960 MHz, offering the longest read range among passive RFID options—up to 12 meters or more. These tags are extensively used in various industries, especially supply chain management, inventory tracking, and retail.
A significant advantage of UHF RFID tags is their ability to track multiple items simultaneously. The UHF Gen2 standard ensures compatibility across global logistics networks. RAIN RFID systems comply with international regulations, further enhancing performance in large-scale operations.
Additionally, semi-passive RFID or battery-assisted passive (BAP) tags bridge the gap between passive RFID and active RFID. These active tags extend range and performance by incorporating a small battery. Since the reader and reader antenna send power, BAP tags can function efficiently in environments requiring extended range and faster data processing.
Different Types of Passive RFID Tags by Form Factor
Passive RFID tags, which do not have their transmitter or power source, rely on captured energy from the reader to function. These tags are used in various industries, from retail and logistics to healthcare and industrial asset management.
The two main types of passive RFID solutions are inlays/labels for flexible applications and hard tags for durability. Depending on their design, passive RFID tags broadcast signals for different use cases and environments. Below, we explore the various types of passive RFID tags by form factor.
1. Labels/Stickers
Labels and stickers are among modern tracking systems’ most common passive RFID solutions. These thin, adhesive passive UHF tags are widely utilized in packaging, inventory management, and supply chains.
As part of UHF RFID systems, these labels are cost-effective and can be mass-produced for seamless integration. Since they can embed RFID capability into everyday operations, they are particularly beneficial for logistics and retail environments where real-time RFID tracking is essential.
2. Cards/Badges
RFID-enabled cards and badges are widely used in real-time applications like access control, public transport, and cashless payment systems. These tags, often operating in IF and HF frequency bands, are credit-card-sized and incorporate security features like encryption.
If RFID systems need secure identification, cards and badges provide a reliable solution. For example, hotels use RFID keycards to grant seamless room access, and workplaces deploy them for employee identification and secure entry.
3. Hard Tags (Epoxy/Plastic)
Hard RFID tags are rugged and designed for RFID tracking in industrial and outdoor settings. These tags, often made of epoxy or plastic, can withstand extreme temperatures, moisture, and physical impact. Tags for passive and active tracking applications may be affixed to equipment, vehicles, or heavy machinery.
While passive UHF tags are common in these scenarios due to their extended read range, some active tags exist for even longer-range tracking. Hard tags ensure durability, making them a critical RFID type in harsh environments.
4. Implantable Tags
Implantable RFID tags are small, biocompatible chips designed for tracking animals and humans. Their unique identifiers make them ideal for pet microchipping, livestock management, and even patient monitoring in healthcare.
Typically operating on LF or HF frequencies, these tags allow veterinary professionals and hospitals to scan and retrieve critical data efficiently. As UHF RFID systems evolve, more advanced implantable solutions may emerge for enhanced real-time tracking.
3.5 Specialized RFID Tags
On-metal RFID tags are engineered to function on metallic surfaces without interference. Traditional RFID tags struggle with metal because it can reflect or absorb radio signals,
However, these specialized tags ensure an accurate signal to the tag even in challenging environments. They are commonly used for systems such as asset management and industrial tracking.
Laundry RFID tags are designed to endure harsh washing processes, high temperatures, and chemical exposure. They are primarily used in hotels, hospitals, and commercial laundries where automated linen sorting and tracking are necessary. Their durable casing ensures that they remain functional despite repeated wash cycles.
How to Choose the Right Passive RFID Tag for Your RFID System?
Selecting the right passive RFID tag ensures optimal tracking and inventory system performance. Whether RFID tags work in retail, healthcare, logistics, or access control, the right choice depends on factors like environment, material compatibility, and frequency range.
Unlike active tags, passive RFID tags don’t have their own transmitter but rely on energy from the reader for data transfer. If RFID systems are used in various industries, choosing the best tag means balancing longer read range, durability, and cost. Here’s how to make the right selection:
Key Factors to Consider
- LF (Low Frequency): Often used in animal tracking and industrial applications where materials like metal or liquids interfere with signals.
- HF (High Frequency) Includes near-Field Communication (NFC), which is ideal for access control and payment systems.
- UHF (Ultra-High Frequency): Offers a longer read range, making it perfect for logistics, asset tracking, and RAIN RFID Alliance-compliant systems.
- Read Range: Short-range tags work best in secure applications like NFC, while longer-read ranges suit warehouse tracking.
- Material of the Tagged Item: If RFID systems are used on metal or liquids, specialized RFID tags work better with protective coatings or spacers.
- Environmental Conditions: Tags must withstand extreme temperatures, moisture, or exposure to chemicals in industrial or outdoor settings.
- Mounting Method: Adhesive-backed tags work well on smooth surfaces, while screws or embedded designs are better for rugged environments.
- Compliance & Cost: Ensure the tag meets RAIN RFID Alliance or industry standards and aligns with your budget.
5. Conclusion
Passive RFID tags are crucial in modern tracking and automation and offer cost-effective solutions across industries. Unlike active tags, which have their own transmitter and broadcast signals, passive tags rely on energy returned to the reader for data exchange.
From HF RFID technology used in secure access systems to UHF tags for inventory tracking, each type serves a unique purpose. As RFID evolves, businesses can expect improved range, durability, and integration with IoT.
Whether choosing passive or active RFID, understanding how an RFID system works helps optimize operations. With innovation, RFID offers smarter, more efficient solutions.
