[[TitleIndustry]]

what is active rfid and passive rfid

Date:May 23, 2020

Active RFID

 


The first concept is about active RFID. In this case, an on-board power source is used to for operating tags. It may be a battery or a cell, for example, enabling both tag performance and data transmission.


Active RFID applies to several industries, such as construction, public works and security, as well as home automation. Active tags are mainly used for monitoring physical parameters (such as temperature, humidity, movement). This applies in particular to cold chain control in refrigerated trucks. They also make it possible to identify and track people for on-site safety. Lastly, they may also be used for access control or automatic goods identification.


STRENGHTS

Main strength: high distance coverage

Increased information storage capacity compared to passive tags

Tags providing various additional functions

Fast data transfer rate

Possibility to read a large number of labels simultaneously

WEAKNESSES

Tags are costly and have a limited lifespan

These tags are rather intrusive, given their medium size, which makes them visible

COVERAGE / RANGE

Active tags have a very long coverage range, exceeding 500 m. Other technologies (further information in other articles of this blog) make it possible to extend this distance to up to one kilometer.


 


Passive RFID

 


The second case concerns passive RFID. Unlike active tags, passive tags do not include any embedded power source. As an alternative, the reader wave is used as a power source for the chip, in order to modulate the signal and to broadcast the signal back to the reader by back scattering.


 


STRENGHTS

It is low cost.

It is time saving.

It uses flexible materials. In fact, tags may sometimes be made of paper or textile, making them more environmentally friendly (provided that the metal ink used in the antenna also is eco-friendly).

It includes significant highlights such as their small size, lightweight and long lifespan.

STRENGHTS

This device may read only very few labels simultaneously.

Their decreased range and reliability - compared to those provided by active tags - make them less reliable and more fragile.

COVERAGE / RANGE

Passive tags have a 3-level range.


We are talking about short distance with a Low Frequency, when referring to a contact located only a few centimeters away.  

The average distance represents a range held between a few centimeters up to 1m. This is known as High Frequency. For instance, NFC has a reading distance of 10 cm in most cases.

Lastly, the maximum distance extends up to 15m and relies on the Ultra High Frequency technology.

 


To go even further...

 


You may also find a third type of RFID, called semi-passive. Although less famous and therefore less used, this device incorporates some active RFID features (such as a battery placed on the tag, to provide power only at this time) and passive RFID features (for transmission purposes). These tags have a longer lifespan than an active tag and are cheaper. However, they remain more expensive than the passive ones.


Previous: What are the characteristics of RFID tags

Next: rfid details