Active Vs Passive RFID : Difference between active and passive RFID tags
Radio Frequency Identification (RFID) technology is widely used for tracking, monitoring, and authenticating items in various industries. RFID tags are broadly classified into active and passive tags based on their power source and signal transmission method. Active RFID tags contain an internal battery and can actively transmit signals over longer distances, whereas passive RFID tags rely on the reader’s energy to communicate. Understanding the characteristics and use cases of active and passive RFID tags is essential for implementing effective RFID solutions in logistics, retail and access control. In this page we will compare Active RFID vs Passive RFID and discover difference between Active and Passive RFID tags.
Active RFID tag
Active RFID tags have an internal power source, such as a battery, which enables them to transmit signals independently without needing external power from the RFID reader. These tags continuously broadcast their signal at predefined intervals or when triggered by specific conditions.
The key features of active RFID tags are as follows.
➨Power Source: Equipped with an internal battery to power the tag's circuitry and the transmitter.
➨Signal Transmission: Actively transmits signals to the RFID reader, which allows for longer read ranges.
➨Read Range: Typically ranges from tens to hundreds of meters, depending on the power and antenna configuration.
➨Memory Capacity: Can store larger amounts of data due to their active nature.
➨Battery Life: Limited battery life, typically lasting from a few months to several years depending on usage.
Advantages of active RFID tag
1. Longer read range compared to passive tags.
2. Can continuously monitor and transmit sensor data, such as temperature and humidity.
3. More reliable in complex environments with interference or physical obstacles.
Disadvantages of active RFID tag
1. Higher cost due to the internal battery and more complex circuitry.
2. Limited lifespan due to battery depletion.
3. Larger size and weight compared to passive tags.
Applications: Used in asset tracking, vehicle monitoring, real-time location tracking, and environmental monitoring, where long-range and continuous data transmission are required.
Passive RFID tag
Passive RFID tags do not have an internal power source. Instead, they rely on the electromagnetic energy transmitted by the RFID reader to power the tag's circuitry. When the tag enters the reader’s electromagnetic field, it draws energy from the field, activates its circuitry, and transmits its stored data back to the reader.
The key features of passsive RFID tags are as follows.
➨No Internal Power Source: Relies entirely on the RFID reader’s power.
➨Signal Transmission: The tag is powered and activated only when in close proximity to the reader.
➨Read Range: Shorter range compared to active tags, typically ranging from a few centimeters to a few meters.
➨Memory Capacity: Typically lower storage capacity due to limited power availability.
➨Lifespan: Indefinite lifespan since there is no battery to deplete.
Advantages of passive RFID tag
1. Lower cost compared to active tags due to the absence of a battery and simpler circuitry.
2. Smaller size and lighter weight, making them easy to integrate into various objects.
3. Longer lifespan, as there are no batteries to replace.
Disadvantages of passive RFID tag
1. Shorter read range, limited by the power emitted from the reader.
2. Cannot transmit data independently without being powered by an RFID reader.
3. Less suitable for environments with high interference or obstacles.
Applications: Commonly used for inventory management, access control, contactless payments, and product authentication, where short-range identification is sufficient.
Difference between active and passive RFID tags
| Features | Active RFID | Passive RFID |
|---|---|---|
| Power for RFID Tag | Power required for Tag is internally available. | Power is available for tag via energy transfer from RFID reader using RF waves. |
| Battery for Tag | Available | Not Available |
| Tag power requirement | continuously available | available in the range of RF field of the RFID reader |
| Energy Independence | Can operate independently of reader presence. | Requires reader’s presence for operation. |
| required signal strength from reader to tag | Low | High |
| coverage range | 100 meters or more as no constraint on power | 3 meters or less as there is power constraint |
| capacity for multi-tag operation (without movement) | Able to collect data from 1000s of tags using single reader. | collection of data from multiple tags is difficult and un-reliable. Good system can collect 100s of tags within 3 meters of coverage using single reader. |
| capacity for multi-tag operation (with mobility) | collects data from 20 tags at moving speed of 100 mph | collects data from 20 tags at moving speed of 3 mph or less |
| sensor | monitors and records sensor input continuously | read and transfer sensor values only when tag is powered by the reader |
| Data storage | larger capacity for read/write (about 128 KB) | smaller capacity for read/write (about 128 bytes) |
| common frequency of operation | 433 MHz (glabally used) | 862 MHz to 928 MHz |
| Lifespan | Limited by battery life (a few months to several years). | Longer lifespan; theoretically unlimited. |
| Cost | Higher cost due to internal battery and complex circuitry. | Lower cost, simpler design. |
| Use in Interference Areas | More reliable in environments with interference or obstacles. | Less reliable in such environments. |
| Imapcts in business processes | minimal | substantial |
| Application#1 (Area monitoring) | possible using active RFID | not possible using passive RFID |
| Application#2 (High speed multi-tag portal) | Yes | Limited |
| Application#3 (Electronic Manifest) | Yes | No |
Conclusion
Active and passive RFID tags each serve specific purposes depending on the application's needs. Active RFID tags, with their longer read ranges and continuous signal transmission, are ideal for real-time tracking and monitoring applications. In contrast, passive RFID tags offer a cost-effective and compact solution for short-range identification and inventory management. Choosing between active and passive RFID tags should be guided by factors such as read range, cost, power requirements and environmental conditions.
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