6 Questions For Choosing The Right RFID Tag

Along with the development of the Internet of things, RFID(Radio-frequency identification) technology has been applied in many scenarios, including access control, public transportation, cashier, electronic toll collection, apparel management, anti-counterfeiting, enterprise asset management, factory production line optimization, people and equipment positioning management, etc. RFID is becoming one of the technologies that change the way people live. However, there are several kinds of RFID technologies, how to choose the right RFID tag and design the solution is not only related to the cost, time, and quality of a project but also may affect the success of the project.

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

From the power supply mode, the RFID tag is divided into Action mode and Passive mode, Active RFID tag(Bluetooth Beacon) means that the tag is powered by a battery, its main operating frequency is 433MHz, 2.4 GHz, and 5.8 GHz (UWB), while Passive RFID tag means it runs without battery and the tag is activated by the radio sent by an RFID reader; Based on the operating frequency, passive RFID 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 are suitable for specific applications. Their features are described as follows:

• LF RFID Tag operation principle is electromagnetic coupling, its operating frequency is 125 kHz and 134 kHz, can be identified in short distance(less than 5 cm), slow speed, small memory but friendly to metal, biological and liquid material, suitable for item-level identification and biological identification, a typical application is access control, animal identification, auto key, park management, etc.
• HF RFID Tag operation principle is electromagnetic coupling, its frequency range is 13.56MHz, based on a different protocol, identification can be in relatively short distance (less than 5cm), individually, fast speed, high security, usually used in access control, payment, public transportation tickets, transportation card, etc. Or can be in the medium distance (up to 1 meter), fast speed, batch volume, usually used in automation, industrial authentication, laundry management;
• UHF RFID Tag operation principle is electromagnetic emission, its frequency range is 860-960 Mhz, it features long reading distance (up to 30 meters), batch identification (up to 1000units), high reading speed, low cost, typical application are like retail, apparel, jewelry, warehouse, logistics, packaging, brand protection, asset management, equipment maintenance, etc.

Crepak’s consultant often got inquiries like “I want to use RFID for warehouse management, please give me the price of the RFID tag & reader 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:

Dear Sir/Madam, we know you are willing to deploy RFID for your project, in order to provide appropriate RFID products 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?

A scenario is usually a basic description of an RFID project, 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 the best choice for that specific scenario; for example, if the scenario is asset tracking, and bulk reading of tags is needed, ultra-high frequency technology is usually recommended. If the scenario is data capture in the production line or flexible manufacturing, low frequency, high frequency or ultra-high frequency are the choices but for most, the case low frequency and high frequency are better; If the scenario is animal identification, low-frequency tags are usually suggested. If the scenario is real-time indoor location management, automatic inventory checking of assets or equipment, or a non-stop toll system, then an active RFID tag (Bluetooth beacon) is a better choice.

QUESTION 2: WHAT IS THE SPECIFICATION OF THE ASSETS AND HOW IS THE TAG TO BE ATTACHED TO?

RFID Tag is normally attached to an asset, and the specification of the asset is always a key factor for tag sizing, and the attaching ways.

• 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 be 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 the 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 the irregular shape/small size, or there is a specific mounting position, we need to choose a specific tag like round shape, curved shape, or flexible RFID label, glass tube and even very small tag.
• How the tag can be attached? normally there are many ways for tag attaching,  including adhesive, epoxy, screw, rivet, magnetic, tie, welding, and embedding, we need to know the exact way that the tag can be attached, then we choose a proper tag.

QUESTION 3: WHAT IS THE ENVIRONMENT OF THE TAGS TO BE APPLIED?

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 the appropriate product for the specific condition: and the conditions we need to know are:

• Indoor/Outdoor? if it is used in an 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, RFID label or PCB tag may meet the requirements.
• High temperature & temperature shock? If high temperature is required, a high temperature RFID tag is needed, the tag material should withstand high temperature, like FPC, ceramic or PPS, Peek; also, the chipset fixation way is needed to be rugged, like wire-bonding, welding, SMT, etc;
• Chemical? If there is chemical corrosion, we need to be very careful, to know the details of the chemical, what’s the composition? What’s its concentration? Then the tag material has to be stainless steel, silica gel, PPS, 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 a special requirement in a particular industry; Such as in the 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, the tag needs to meet extremely high vibration standard, and in the health care industry, FDA approved is necessary, and for some healthcare application, the 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, a durable RFID tag is needed, and to be mounted in a reliable way, the best way is covered by glue or embedded via injection molding, or welded 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 tags, but it is better to be an RFID label with adhesive or a seal & tamper proof tag.
• If the tag is reused, the most important is the mounting way, the tags need to be easily mounted and removed, and normally we would use a 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 simultaneously, tag memory can be 1 bit to 1Mb：

• If we need to identify a single tag at a short distance, low frequency and high frequency are the best choices, application including animal identification, automated production line tracking;
• If it is for multiple tags tracking at a middle distance or security scenario, high frequency is the better choice, a common application such as contactless Pay, flexible manufacturing, traceability in the automotive industry, data collection and management;
• If it is for long distance or batch identification, ultra-high frequency tags or Bluetooth Beacons can meet the requirements, typical application including inventory checking, goods dispatching or receiving, retail store management;
• An RFID tag chip, usually contains UID, EPC, or User Memory, and there are many RFID chipset suppliers in the market, normally UID is unchangeable, while EPC and User memory are programmable, and their capacity is from 0bit to 1Mbit. In most the case, unique code is used for identification, while assets related data is stored in the database, however, in some specific areas, like work in process management, aviation industry, the data needs to be stored in the tag memory for offline identification, in this case, the tag memory needs to be a bigger size. Also, in some extreme conditions, like automation, the tag needs to be read at high speed, and be written over 1M times, then a FRAM memory chip is necessary.

QUESTION 6: WHAT IS THE BUDGET?

For an application, multiple RFID technologies may meet the requirements, it is not that simple 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 indirect cost or even it can be re-used to save total cost; and in some case, we need to consider about the reader, antenna and deployment cost. A skillful and professional consultant is necessary for an RFID project, they will not only choose a high performance/price ratio tag, but also evaluate the reader, antenna cost, as well as deployment and maintenance cost; Generally speaking, an RFID label is cheaper than an RFID tag with housing or made in a special process, Low frequency and high-frequency tags are expensive but reader and implementation costs are low, ultra high frequency tags cost are low, but reader and implementation costs are high; Active tags & Bluetooth Beacons’ themselves and their implementation and maintenance costs are high, but they can be extended to more applications to bring extra value.

As a summary, we need to ask at least above 6 questions before designing an RFID solution and choosing the right RFID tag, there are already many RFID tags, RFID readers, RFID antennas in the market to meet general requirements, if they are all not applicable, then a customized product is needed, as a professional RFID supplier in the market, Crepak has been developing RFID tags, readers or smart equipment for many clients, if you have any query, please don’t hesitate to inquire our experienced consultant at [email protected]