Types of RFID-Transponders

Energetically, RFID transponders can be divided into three groups:

Passive RFID transponders

RFID - Passive Transponder

Passive RFID transponders receive their required energy completely via a magnetic or  electromagnetic energy field of the RFID read-write device. Data can also be transmitted bidirectionally via this field. These passive RFID transponders are used mostly used.

+  Advantage: cheap, small size   

-  Disadvantage: small range, small memory

RFID - Function of a Passive Transponder

Semi-Active RFID transponders

Semi-Active RFID transponders have their own operating energy source. This serves to supply the logic part (controller, memory). The high-frequency part, which is used for data transmission to the RFID read / write unit, is still obtained from the electromagnetic field.

RFID - Function of Semi-Active Transponder

Active RFID transponders

Active RFID transponders have their own operating energy source as well as their own transmitter. The electromagnetic field of the RFID read-write device is used exclusively for data transfer and no longer for additional energy transfer.

The transponder is normally in so-called "sleep mode" and is only activated by the RFID read-write unit when a data transfer is to take place. This can increase the service life of the transponder's battery up to several years.

RFID - Active Transponder

+ Advantages: lower electromagnetic field, increased range, lower latency (i.e. lower signal runtime), more functions

- Disadvantages: large, expensive