RFID Transponders

RFID Transponders

RFID Transponders

The term RFID transponder is a combination of the words transmitter and responder and is also often referred to as RFID tag or RFID label. The transponder has the task of unequivocally identifying goods using the information saved about them.

What are RFID transponders made up of?

An RFID transponder comprises a microchip which is connected to an antenna (inductor or dipole). The data is saved on the chip and transmitted with electromagnetic waves to an RFID reader. All of the data is exchanged by modulation using the electronic coupling method.

Active vs. passive RFID tags

Active RFID tags


Active tags comprise an electronic microchip, an antenna, a battery and an integrated transmitter. The integrated transmitter sends energy directly to the reader instead of reflecting the energy transmitted from the reader back to the tag. This makes it possible to achieve a more extensive reading range. In addition to the greater reading distance, active tags support numerous additional functions, such as integrated sensors, an expanded data memory and more logic functions.


Since active tags hold more components and support a variety of additional functions, they normally require more space than the other tag types. The costs for active RFID tags are also higher due to the additional materials and special features. They also have a shorter life span as the transmitter and the additional moving parts require more power.


Active RFID tags are mainly suitable for processing valuable goods which require uninterrupted real-time tracking and/or monitoring of the surroundings.


Passive RFID tags


As described above, passive tags are made up of two parts: an electronic microchip and an antenna. They do not contain any other moving parts or batteries. Power is supplied to the tags during reading via a so-called inductive coupling.


Generally speaking, inductive coupling works as follows: If the reader/the antenna and the tag are in the same reading range, the reader/the antenna generates a  magnetic field  which triggers a coupling of the tag and reader. During coupling, power from the reader is transmitted through the tag’s conductive antenna and onto the tag itself, thus making it possible to read the data saved on it.


Due to the fact that the tags are only operated when needed, they mostly have a long and stable lifetime. The fact that they do not include any moving parts reduces their probability of failure.


Their long life span and high reliability make passive RFID transponders inexpensive and particularly suitable for long-term warehouse applications. They are useful when the labeled goods do not need to be tracked for a long time.

3 categories of passive RFID tags

Read-only RFID tags



Read-only RFID tags are only written once by the manufacturer and can be subsequently read as often as required. It is then no longer possible to add, overwrite or delete information.

Write once, read many (WORM) RFID tags


Unwritten WORM RFID tags are delivered once by the manufacturer and can have data written on them once by the user. Similar to read-only RFID tags, they can be read out any number of times. However, it is also no longer possible to add, overwrite or delete information here.

Read and write RFID tags


Read and write RFID transponders of this category are rewritable. This allows for any amount of reading and writing access for adding, overwriting or deleting data. If necessary, reading or writing access may be limited for this RFID tag.

Low frequency vs. high frequency vs. ultra-high frequency RFID tags

RFID labels with low frequency transponders (LF = 125 kHz)


Long waves in a frequency range of between 125 kHz and 135 kHz are used in LF RFID systems. The transmission range is only approx. 10 cm, yet they still remain a reliable and fast solution. RFID systems have already established themselves in areas of application such as production, assembly or access control, as well as in the animal identification sector.

RFID labels with high frequency transponders (HF = 13.56 MHz)


HF RFID systems use short waves with a working frequency of 6.78 MHz, 13.56 MHz or 27.125 MHz and are characterized by their high transmission rate. A frequency of 13.56 MHz is viewed as being the global standard for RFID labels in the  logistics sector. High frequency RFID systems offer a medium to high reading and writing distance of up to 3 meters.


RFID labels with ultra-high frequency transponders  (UHF = 860 MHz – 950 MHz)



RFID systems in the ultra-high frequency range make it possible to achieve a high range and transmission speed, and work in a range of 860 to 950 MHz. The reading and writing distance can be up to 20 meters. A range of up to 100 meters is possible in systems with active transponders.


Share by: