How to choose the right RFID tag | Crepak
How to choose the right RFID tag

How to choose the right RFID tag

15 Jan 2019

How to choose the right RFID tag?

Along with the development of Internet of things, the RFID tag has become more and more popular, from the access control, public transportation, cashier, electronic toll collects, or apparel management, anti-counterfeiting, to enterprise asset management, factory production line optimization, people and equipment RTLS, RFID (radio frequency identification) is becoming one of the technology that change the way of people living. However, there are several kinds of RFID technologies . How to choose the right RFID technology and design the optimal scheme is not only related to the cost, time and effect of the project, but also may affect the success of the project. 

Let’s review different rfid technologies and classification before discuss the RFID tag sizing skill:

from the power supply mode, the RFID electronic tag is divided into Passive and Active mode, Active tag means that the tag is powered by battery, its main frequency is 433MHZ, 2.4 GHZ and 5.8 GHZ (uwb), and Passive tag means it hasn’t battery and the tag is activated by the radio sent by the reader; and passive tags can be divided into 3 categories, low frequency (125-134 KHZ), high frequency (13.56 MHZ) and ultra high frequency (860-960 MHZ). different RFID technologies own their specific features, advantages and disadvantages, which makes them to be used for different application, and their features are descried as following:

Crepak’s consultant often got inquiries like”I want to use RFID for warehouse management, please give me the price of the RFID tag and lead time”; this kind of simple question always makes us confused to make a proposal, since the information is not enough for sizing and quotation, therefore, our usual reply is:

Sir/Madom, we know you are willing to use RFID to solve your problem, in order to provide an appropriate product for your project, we need to clarify a few things firstly, and these questions are the base for RFID tag sizing, also it is the essential skill for a good RFID solution; 

QUESTION 1: WHAT IS THE SCENARIO?

Scenario is usually a basically description of a RFID project, scenarios is including the project background, operating process, pain point, expected benefit from the RFID deployment, etc.; For a senior RFID tag consultant, he would evaluate to know what kind of RFID technologies is applicable based on the scenario description; for example, if the scenario is asset tracking, and volume tags need to be read once, ultra-high frequency technology is usually recommended. If the scenario is data collection in production line or flexible manufacturing, both high frequency or ultra-high frequency are choices but for most of the case HF is better; If the scenario is animal identification, low-frequency tags are usually suggested. If the scenarios is real time indoor location management, automatic inventory checking of assets or equipment, or non stop toll system, then active or ultra-wide band is a better choice. 

QUESTION 2: WHAT IS THE SPECIFICATION OF THE ASSETS?

RFID Tag is normally attached to an asset, and the specification of asset always a key factor of tag sizing, the tag maybe not able to be identified if the sizing is wrong; 

  • What is the material? metal, liquid, or other material? If it is metal or liquid, and UHF/HF RFID technologies are applied, we need to choose on metal tag, otherwise the tag reading distance will be very short or even can not been read; if it is non-metal/liquid, or LF/Active RFID technologies are applied, we would choose both on metal and non metal tag, but non metal tag is better; 
  • What is the mechanical spec of the asset? If the asset is big size, square or rectangle shape, no limitation on the position that the tag to be attached, most of the tag can meet the demand; if the asset is irregular shape/small size, or there is specific mounting position, we need to choose a specific tag like round shape, curved shape, or flexible, glass tube and even very small tag, and maybe we need to look for a specific way to mount the tag, including welding, magnetic fixture, tie or special adhesive/glue;

QUESTION 3: WHAT IS THE ENVIRONMENT OF THE TAG TO BE USED IN?

Internet of Things, the things are existing at everywhere, it is difficult for one tag to be used in all kinds of environment, we need to choose appropriate product for specific condition: and the conditions we need to know are:

  • Indoor/Outdoor? if it is used in outdoor environment, the tag is better to be enclosed with a high iP grade housing, and the housing should resist ultraviolet rays, rain, water and so on;  if the tag is for indoor use, ordinary RFID inlay, label or PCB tag may meet the requirements. 
  • High temperature/temperature shock? If high temperature is required, tag material should be withstanding in high temperature, like FPC, ceramic or PPS, Peek; also, the chipset fixation way is needs to be rugged, like wire-bonding, welding, SMT etc; 
  • Chemical? If there is chemical corrosion, we need to be very careful, we need to know the details of the chemical, what’s the composition? What’s its concentration? The material has to be stainless steel, silica gel, PP, Peek, or other special metal or plastic, also, we need to have a test to make sure it is adaptable;
  • Vibration/Shock? If there is such a special requirement, it is necessary to choose the material resistant to impact and vibration and high reliability chip as well as its bonding method, normally the tag should have a housing; 
  • Particular Industry? There is special requirement in particular industry; Such as in aviation industry, material need to conform to the requirements of the flame retardant, in the Oil&Gas industry, the tag has to be ATEX certified; in the railway sector, tag needs to meet extremely high vibration standard, and in the health care industry, FDA approved is necessary, and for some application, tag needs to withstand in sterilization process;

QUESTION 4: WHAT IS THE REQUIRED LIFETIME OF THE TAG? 

  • if the tag is used for lifecycle management, it need to be rugged, and reliable fix way, the best way is embedding by glue or embedding via injection molding, or welding onto the asset, and sometimes we may fix it onto the PCB board via SMT process; 

  • if the tag is for disposal use, we can choose all kinds of tag, but it is better to be RFID label with adhesive or tag with seal/Tie; 
  • If the tag is reused, the most important is the mounting way, the tags needs to be easily mounted and removed, and normally we would use cable tie, magnets fixture or hanging;

QUESTION 5:WHAT IS THE NEEDED RF PERFORMANCE AND MEMORY?

Reading distance of RFID tag can be 1mm to 300 meters, and tag quantity that can be identified is from 1 to 1000 at the same time, tag memory can be 1 bit to 1Mb:

  • If we need to identify single tag at short distance, low frequency and high frequency are the best choice, application including animal identification, automated production line tracking;
  • If it is for multiple tags tracking at middle distance or security scenario, high frequency is the better choice, common application such as contactless Pay, NFC and flexible manufacturing, traceability in automotive industry, data collection and management;
  • If it is for long distance or batch identification, ultra-high frequency or active can meet the requirements, typical application including inventory checking, goods dispatching or receiving, retail store management; 
  • For a RFID tag chip, it usually contains UID, EPC or User Memory, and there are many RFID chipset supplier in the market, normally UID is unchangeable, EPC and User memory are programmable, and its capacity is from 0bit to 1Mbit, normally HF chip memory is bigger than UHF chip while UHF chip memory is bigger than LF; we would choose appropriate chip for different application;

QUESTION 6: WHAT IS THE BUDGET?

For one application, there may be multiple RFID technology can meet the requirements, and multiple RFID tags can meet the demand, it is not a simple way to choose the lowest cost product, sometimes tag cost is low but the operation cost is high, or tag cost is high but due to its operation way, it can reduce more indirect cost or even it can be lower cost via recycle use; a skillful and professional consultant is necessary for a RFID project, they will not only help to size a high performance/price ratio tag that can meet the application requirement, but also need to evaluate the reader/antenna cost, convenience &cost of deployment, or even deployment cost;  Low frequency and high frequency tags are expensive but reader and implementation costs are low, uhf tags cost is low, but reader and implementation costs are high; Active tags’ implementation and maintenance costs are high, but it can be used in many scenario and not sensitive on environment;

if you have any query in your case, please don’t hesitate to talk to our talented consultant at sales@crepak.com;