Basics of contactless smart card technology: RFID transponders offer inexpensive and easy-to-use identification and authentication. They are widely used today. You will encounter the versatile chips at the ski lift hub as well as in security cards, key cards or laundry labels.
The acronym RFID is short for Radio Frequency Identification. The identification system consists essentially of a microchip and a small coil that serves as an antenna. On the chip a certain code is stored which, depending on the design, is permanently implemented or changeable. Most transponders do not require their own power supply, so they work purely passive.
The chips are read with an electromagnetic alternating field, which is built up by a reader. The pulsating magnetic field activates the chip and creates a low voltage in the coil. This serves as a power supply. RFID chips are very frugal: about 0.35 microamps are enough for a trouble-free transmission.
The RFID microchip changes the field emitted by the reader. The reader can then use this response, which is modulated in the alternating field, to determine specific data of the marked object, for example a serial or inventory number.
Sophisticated technology, especially with the readers, makes reading even in difficult conditions possible. For example, the reader changes the orientation of the field (polarization direction). Thanks to this so-called circular polarization, reading is independent of the angle of reader to RFID tag. RFID chips send after a randomly determined delay. This avoids digital voice confusion, even if many RFID chips are within the range of the reader.
Today, RFID transponders are used in diversified areas – always with the task of assigning an individual digital identity to a person or object.
For example, RFID tags help with inventory in a warehouse or store. Where previously laboriously printed labels had to be grasped by hand, today one has the entire inventory always in view thanks to the RFID functionality. Today contactless identification technology also serves to track the goods in the logistics chain.
Radio Frequency Identification can even protect the product against theft: If the transponder at the cashier is not deactivated, the reader will activate an alarm at the exit.
The RFID functionality is also widely used in security cards and access control systems of all kinds. RFID chips open locks, deactivate alarm systems and even make it possible to track visitors within the factory premises.
Many car manufacturers now offer keyless locking systems. The owner only needs to approach his vehicle with an RFID card in his pocket and can get in immediately. The RFID transponder then also deactivates the immobilizer.
RFID chips can get under your skin, literally. For examples, riding horses, zoo animals or pets can get tiny RFID transponders implanted for identification purposes.
While RFID transponders were originally designed primarily for logistics, the trend in the future is increasingly turning to authentication applications, even for transactions in the financial sector. Here, the RFID identification can replace the insecure system of static passwords. A growth market of the future are RFID-based payment systems. For safety reasons, devices with a very short reading distance are used (Near Field Communication, NFC). An example for this is the GiroGo system, which is already being offered by many banks and savings banks on their girocards. You can load a certain amount of money onto a payment card, which you can then use for cashless paymets of smaller purchases – literally with a wipe. This way, the queues in front of kiosks or supermarket checkouts can be significantly reduced.
Schematic representation of the RFID functionality