Reliable contactless data capture – 
in industry, logistics, and medical technology

RFID reading refers to the process by which an RFID reader retrieves data stored on an RFID tag, RFID chip, or RFID transponder wirelessly via radio waves. This technology—also known as Radio Frequency Identification—is the central step in every RFID application: only through reliable reading are identification, tracking, and process control possible throughout the entire supply chain. Range, read speed, and read accuracy depend directly on the frequency band used, the quality of the transponder, and the environmental conditions. The UID (unique identification number) and the stored content of the RFID tag are crucial for the secure and unambiguous assignment of objects, people, or goods—in industry, logistics, retail, and medical technology.

PMG develops and manufactures RFID labels for a wide range of applications, as well as tags and transponders specifically designed to deliver stable and reliable reading results—from individual identification to automated batch capture.

What does RFID reading mean?

During RFID reading, the RFID reader emits an electromagnetic field that activates the transponder and triggers data transmission. Passive transponders derive all their energy from this field and do not require their own power source. The read RFID information—typically a unique identification number such as the EPC (Electronic Product Code) or the UID (Unique Identifier)—as well as other stored data on the RFID chip (IC) is transmitted by the reader to a higher-level host system, such as a warehouse management, production planning, or inventory management system. In addition to writable RFID tags, there are also so-called read-only tags, whose data can only be read but not modified. RFID tags are used to label and identify objects, people, or animals. Compliance with standards is crucial for the compatibility and security of RFID systems.

RFID systems with different transponder types operate in various frequency ranges, such as the LF (Low Frequency) range, typically at 125 kHz. The selected frequency influences the possible distance between the RFID tag and the reader, as well as the specific application, such as access control or animal identification. There are various methods for reading and data transmission, which vary depending on the application and security requirements.

An Overview of Reading Variants

In industrial practice, three types of reading are used, each characterized by different methods and
standards in RFID systems:

Stationary Reading

Stationary RFID readers are permanently mounted at a fixed point in facilities, conveyor lines, or access areas. Objects are automatically detected as they pass through—without manual intervention.

Typical features:

• Fully automatic, continuous detection
  
• Integration into conveyor systems, security gates, or gate systems
  
• Immediate data transmission to host systems
  
• High processing speed through parallel batch detection

Typical applications:

• Intralogistics and goods receipt/shipment
  
• Production control and assembly lines
  
• Access controls in secure areas where various stationary and mobile RFID readers are used

Mobile Reading

Mobile RFID handheld readers enable flexible reading of transponders without a fixed infrastructure.
The compact devices store data temporarily and transmit it to the host system via Wi-Fi or a docking station.

Typical features:

• Flexible use without a fixed installation
  
• Suitable for irregular or geographically dispersed reading operations
  
• Compact, handy design
  
• Offline-capable with subsequent data synchronization

Typical applications:

• Inventory and stock verification
  
• Maintenance and repair
  
• Tool and instrument tracking using customized RFID solutions
  

Portal and Gate Reading

In portal or gate reading, objects or load carriers pass through a defined reading gate that combines multiple antennas. This variant is particularly suitable for simultaneously detecting many transponders in a short period of time.

Typical features:

• Simultaneous reading of multiple RFID tags (batch detection)
• High throughput rates
  
• Precise spatial delimitation of the read range

Typical applications:

• Goods receipt and shipment in logistics centers
  
• Pallet and container tracking
• Retail and smart stores, as found in various application areas for identification solutions

Factors Affecting Reading Quality

The reliability of RFID reading depends on several technical and physical factors:

• Frequency band and distance: UHF enables long ranges and fast batch reading, but is more susceptible to interference from metal and liquids. HF (Near Field Communication) is suitable for controlled individual readings at short distances. In the LF range, particularly at 125 kHz, the distance between the reader and the transponder plays a decisive role in read quality. The choice of frequency (e.g., 125 kHz in the LF range) significantly influences identification, transmission range, and the type of application, such as in access control or industrial conveyor technology.
  
• Transponder design: Antenna size, chip type (e.g., LF, HF, UHF tags), and the substrate material of the RFID tag significantly determine read performance on various surfaces.
  
• Material properties of the object: Metallic or liquid-filled surfaces can attenuate or reflect the electromagnetic field and require specially designed transponders.
  
• Reading distance and angle: Range and reading angle depend on antenna geometry, transmission power, and frequency.
  
• Environmental conditions: Sources of electromagnetic interference, temperature, or confined installation spaces can affect reading performance.

PMG develops custom solutions such as RFID tags for demanding environments, including PMG RFID FlagTags,
PMG onMetal RFID tags, or PMG IronPerform 6025, which are designed.

Choosing the right selection strategy

The selection of the appropriate reading strategy depends on several factors:

• Type and frequency of reading operations (continuous or sporadic)
  
• Number of transponders to be read simultaneously
  
• Material properties and geometry of the tagged objects
  
• Available infrastructure and integration requirements
  
• Requirements for process speed and degree of automation

PMG assists in the design of suitable RFID solutions and tailors label and tag designs specifically to the respective reading configuration, from standardized RFID product solutions to custom RFID label development.

RFID reading as the foundation of every 
automated identification system

RFID reading is not an isolated technical process, but rather the heart of every RFID-based process chain. Modern RFID technology and RFID systems enable the automation and increased efficiency of processes - particularly in the food and automotive industries, as well as other logistics and production environments, by supporting the automatic identification and localization of objects. Unreliable read results lead to process interruptions, incorrect information in the host system, and increased post-processing effort.

Through a combination of material-optimized transponder designs, practical development, and expert consulting, PMG ensures that RFID tags and labels deliver reliable results for all applications in any reading configuration - regardless of frequency band, reader type, or operating environment.

FAQ

What is RFID reading?

In RFID reading, the data stored on an RFID transponder is retrieved contactlessly by an RFID reader using radio waves. The abbreviation RFID stands for “radio frequency identification” and describes a technology for the contactless, automatic identification and tracking of objects, people, or animals.
An RFID system consists of an RFID tag containing an RFID chip (also simply called an IC). This chip stores various data, known as the content, such as a unique identification number (UID), which serves for unique identification and authentication. The distance between the RFID reader and the RFID tag plays an important role in the system’s function and range.
There are various types of RFID tags, including so-called read-only tags, where the stored data can only be read but not modified. This technology enables the efficient automation of processes in areas such as logistics, food labeling, automotive manufacturing, access control, and inventory management.

What types of RFID reading are there?

There are various types of reading, including stationary reading, in which fixed readers automatically detect objects; mobile reading, using handheld readers for flexible applications; and portal or gate reading, which enables the simultaneous detection of multiple RFID tags within defined areas. For each reading method, RFID systems—consisting of transponders, readers, and software—are configured accordingly. Different methods and standards are used to ensure efficient and secure identification, as well as the compatibility and reliability of the RFID systems.

How do materials and the environment affect reading quality?

Materials such as metal or liquids can interfere with, attenuate, or reflect the electromagnetic field, which can impair reading range and accuracy. Environmental factors such as sources of electromagnetic interference or temperature also play a role in the reliability of the readout.
In addition, the distance between the reader and the transponder, as well as the use of specific frequency ranges—such as LF at 125 kHz—significantly influence read quality. Compliance with standards is crucial to ensuring reliable and consistent read quality under varying environmental conditions.

What role does frequency play in RFID reading?

Frequency determines range and application: UHF is suitable for long ranges and fast batch reading, while HF (Near Field Communication) is used for short distances and controlled individual reading. LF frequencies, such as 125 kHz, are frequently used for short-range applications, such as access control or in industrial conveyor and transport systems. The choice of frequency and compliance with relevant standards are crucial for ensuring interoperability, reliability, and the appropriate application of RFID technology.