RFID at a glance.

What is RFID?

RFID stands for Radio Frequency IDentification. Together with barcodes and camera systems (for example) RFID solutions are a member of the family of auto-identification (Auto ID) technologies.

What are the components of an RFID system?

: Reader, label and connection

An RFID system consists of the following components:

Transponder (tag/smart label) with data memory and antenna
Read/write unit (reader) with antenna
Host/SPS with data processing software

How does RFID technology work?

Unlike with optical systems, an RFID transmission works without a line of sight via an air interface. A reader transmits electromagnetic waves, thereby generating an electromagnetic energy field and supplying the transponder with energy. The individualized data or numbers stored in the memory of the RFID transponder can be read out and/or modified.

While reading/writing, the reader’s software controls the actual process. In addition, the system uses RFID middleware with interfaces to ERP systems and databases.

What individual components are there and what are their functions and features?

Transponder
An RFID transponder basically consists of a chip (storage), an antenna (transmitting and receiving) as well as a substrate material. The transponder may be complemented (for example) by an additional cover film or an adhesive coating for fastening.

Chip
The main functional component of an RFID transponder is the chip. The required read/write speed, encryption, data volume to be stored and other criteria determine the selection and dimensioning of the chip.

Antenna
Size, shape and frequency of the antenna influence the range of the RFID system.

Version: inlay
An inlay is the simplest version of an RFID transponder. It consists of a substrate film onto which the chip and antenna are combined. Inlays can be converted into labels or hardtags.

Version: RFID label or RFID tag
Self-adhesive RFID labels or tags integrate an inlay into a label format. The substrate material is provided with an adhesive coating to ensure the desired adhesion. An additional cover coating is applied on top of the inlay. This coating can be printed with additional information and/or design elements such as logos and inscriptions by digital printing. Many applications use RFID labels in combination with barcode solutions.

Version: hardtag
To protect inlays from external influences, they are embedded in plastic casings. These so-called hardtags ensure RFID functionality even in rough environments.

Version: casting with PU resin
Another option is casting the inlay into a PU resin coating. Due to the self-healing and pressure-compensating surface RFID inlays withstand even extremely high loads.

: Composition of an RFID label

: Composition of an RFID transponder with PU casting

What are active transponders? What are passive transponders?

Passive transponders are exclusively activated via the electromagnetic field of a reader. Active transponders have their own power supply.

Active transponders are specialized transponder versions used whenever additional functions (i.e. continuous monitoring of a cold chain via an RFID transponder) are required in addition to the basic RFID functionality. In exceptional cases active systems are used to increase the range of the RFID transponder.

How does the frequency used influence an RFID system?

Depending on the desired use and application, the frequency ensures data exchange between the transponder and the reader of an RFID system. The physical characteristics, and thus important system properties such as reading range, reading speed and water penetration, vary according to the frequency.

Frequencies:

Low frequency (LF: <135KHz)
High frequency (HF: 13.56 MHz)
Ultra-high frequency (UHF: 840...960 MHz)
Microwave frequency (MW: 2.45 GHz)

What interfaces can be used to connect readers to an IT system?

Readers can be connected to IT systems via different interfaces including RS 232, RS 422, RS 485 or USB, LAN as well as WLAN. For industrial applications, connections via fieldbus systems like profibus or CAN bus are possible as well.

Where can RFID technology be used?

RFID solutions can be used wherever processes are to be simplified and made transparent.

Key uses currently include:

Production control
Identification
Authenticity features/authenticity protection
Logistics and container management
Animal identification
Payment functions
Contactless chip cards
Management of goods and inventories
Position identification
Time clocking
Admission control

What savings potential do RFID solutions offer?

Time savings through:

Touchfree (remote) data exchange
Parallel identification of multiple objects
Nearly 100 % first reading rate
No line of sight required for data acquisition
Flexible label positioning
Scratch resistance
Optional: maximum resistance against chemical or mechanical influences
No maintenance required

Process optimization through:

Fully automatic processing
Space-saving application
Relief of the load on the software environment
On-site proof of information
In-process storage of data
Reduction of error sources
Reusability
Subsequent printability
Data may be complemented/edited
Data protection available

What differences are there between RFID transponders?

Additional functions:
Depending on the application, tags with different properties are used. For example, there are tags to which data can be written once or several times, tags that know when they have to respond to inquiries, or tags which are protected by encryption.
Storage capacity:
The storage capacity of a transponder may range from 1 bit to several Kbytes.
Energy supply:
Passive transponders draw their operating voltage from the electromagnetic field generated by the reader.
Semi-passive transponders have an additional power source (e.g. a battery) for the memory or supply of the sensors. However, this power source is not used for data transmission.
Active transponders use additional batteries also for data transfer and thus achieve a higher range.
Range:
The range of the RFID tag results from the operating frequency, power output, antenna dimensions as well as ambient conditions.
The maximum range with low frequencies (LF) is 50 cm, with high frequencies (HF) 1 m, with ultra-high frequencies (UHF) 7 m, and with micro-wave frequencies more than 10 m.
Frequency:
The following frequencies are mainly used for applications:
– Low frequency (LF: <135 KHz)
– High frequency (HF: 13.56 MHZ)
– Ultra-high frequency (UHF: 840...960 MHz)
– Microwave frequency (2.45 GHz)
Format/size and substrate:
RFID labels vary in terms of format/size and design. Solutions can be individually adapted regarding shape and adhesion properties. As data transmission may be influenced by various factors via the electromagnetic field, special solutions are used (for example) for metallic substrates.

Can RFID technology be combined with barcode solutions?

Yes, absolutely. The two technologies exchange information in different ways. Therefore, the systems complement each other, perform valuable services in different fields of application and can be efficiently used in combination as well.

Can data on transponders be protected from unauthorized access?

Data on transponders can be specially protected by encryption. This prevents unauthorized reading, overwriting of or tampering with data. Specialized solutions are available to frustrate any attempt at non-destructively detaching a label, e.g. by using ((rfid))-TamperProof Labels or an ((rfid))-Inmold Solution.