Similar to a radio that broadcasts in MW or VHF, an RFID system likewise uses radio waves for communication. RFID applications are fundamentally restricted to ISM-wave bands (from the fields of Industry, Science and Medicine) to avoid a reciprocal interference of the radio systems. Thus an undisturbed exchange of data is ensured.
In order to conform perfectly to the particular requirements, RFID systems work at different frequency ranges. In the range of the passive application three frequency ranges can be distinguished: low-frequency, high-frequency and ultra-high frequency.
Low Frequency (LF)
In the area of low frequency of between 100 and 135 kHz the benefits are in the low-cost of production and its flexibility with respect to the area of application: because they possess a high penetration rate (for example, through water or organic material) and a high effectivity around metals as well as at extreme temperatures or humidity, LF systems can be used in many areas.
The robustness of the system makes it ideal for use above all in industrial production where it can be employed in the systematic monitoring and tracing of orders or production parts. The permitted high transmitting power additionally increases the system’s radius of operation.
High Frequency (HF)
The middle frequency range of between 10 and 15 MHz improves the read range and the data transfer rate of the passive RFID systems in comparison to the lower frequency range. Through a middle data rate of 26 kBit/s, larger amounts of data can be more quickly transferred in the HF range. The areas of application are here also versatile and are increasingly expanding.
The systems that operate in the frequency of 13.56 MHz are employed in object identification, logistic management of merchandise, control of production processes, quality assurance and control, time recording, cost accounting and retail security. Through the higher pulse frequency and data transfer rate, ciphering methods can also be made feasible. In the long run the conditions governing RFID technology in this frequency range will be additionally improved by processes of innovation.
Ultra High Frequency (UHF)
RFID systems in high frequency ranges from 868 to 915 MHz achieve the largest read range. Correspondingly, the data transfer rate improves: the data rate between the RIFD transponder and the reader in the UHF area occurs normally in real time (full duplex procedure). Because of the high production costs UHF systems are only employed in long-term transponder devices. A popular example for an application area for UHF systems is the control and monitoring of logistics processes or the organization of electronic toll- or freight-waggon systems
Generally, increasing frequency involves an improvement in the read range as well as the speed of data transfer. The choice of frequency must, of course, always be decided in connection with the area of application and place of installation of the RFID system.