RFID – The technology
There are various RFID transponders, some of which differ greatly from one another. In principle, the structure of an transponder includes an antenna, an analog circuit for receiving and transmitting, a digital circuit and a permanent memory.
RFID transponders can have a rewritable memory in which information can be stored during their service life.
The key figures also differ depending on the area of application, e.g:
- Radio frequency
- Transmission rate
- Service life
- Cost per unit
- Memory capacity
- Range of functions
For special applications, cryptographic modules or external sensors such as GPS can also be integrated into the RFID transponder.
The RFID transmitter/receiver units also differ in terms of functionality and appearance. This makes it possible to integrate them directly into racks or personnel gates (e.g. for border clearance).
Passive vs. active
The first classification is based on the type of energy supply for the transponders. Small, battery-free RFID transponders(passive transponders) must obtain their supply voltage from the radio signals of the base stations. Active RFID transponders, on the other hand, achieve a considerably greater range with their own power supply and have a greater range of functions, but also cause considerably higher costs per unit.
Communication problems
The large number of different devices and tags are rarely fully compatible with each other. The frequencies used and preferred standards vary greatly from region to region.
Communication problems can also occur with products with a high water content (e.g. yoghurt, mineral water, etc.) and when used on objects with metal parts (e.g. shopping carts, car parts, etc.). These can further reduce the already weak radiation of passive RFID transponders. A similar impairment can occur if the RFID transponder is attached directly to products with a high density.
You can find more information on RFID under RFID systems.
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