I prefer to think of the decision-making process for the proper RFID tag as a large funnel with all of the possible RFID tags at the top, and with each question you ask yourself, you remove more tags from the funnel until only the right tag for your application remains.
What RFID Technology Is Best For Me – Active Or Passive?
After you have selected RFID as your technology of choice one of the first questions you may ask is whether or not you should use an active RFID tag or a passive RFID tag in your application. The answer to that question, and many others when it comes to RFID-related questions, is “it depends.
Let’s look at both options. First, let’s examine passive tags. Passive tags do not have their own power source. First, they are less expensive than their active counterpart. Second, because they do not have a battery, they will last longer than an active RFID tag. Third, again because passive tags do not have a battery, they tend to be smaller and more lightweight than active RFID tags.
Active tags have an onboard power source used for transmitting, usually a battery. The tag uses the battery to power its integrated circuit (IC). They have more memory which means they can store more data. Second, due to their battery-powered ICs, they have longer read ranges than their passive counterparts. However, as I alluded to above, active tags are more expensive, have a shorter lifespan, and are bulkier than passive RFID tags.
For the purpose of this article, I am going to assume a passive tag will work best in your application.
Choosing the right Frequency
Next, in order to select the best tag for your application, it is critical to understand the various frequencies available with passive tags. RFID frequencies are classified as low frequency (LF), high frequency (HF), and ultra-high frequency (UHF).
The answer to which frequency to use is the same as the response to whether to use active or passive RFID: “it depends.” It depends on the nature of the application and the product being tracked in this scenario. Low-frequency RFID tags (125 – 134 kHz) are commonly employed for access control and animal tracking applications, for example. They have a restricted read range, but because of their long wavelength, radio waves can penetrate metallic surfaces more easily than other frequencies.
Next, high-frequency RFID tags (13.56 MHz) are appropriate for situations where an item’s closeness to another item, such as library books, may be an issue. Another potential application is access control, which is used to track the flow of patients in hospitals, medical clinics, and other healthcare settings. NFC, or near-field communication, is a type of high-frequency communication that includes an NDEF statement that permits information to be transmitted between two devices, allowing for contactless payments. These tags have substantially shorter read ranges than their UHF counterparts.
Finally, we must consider UHF, or ultra-high frequency, RFID tags. UHF tags (860-960 MHz) are generally found in more open settings, such as warehouses and manufacturing plants, where speed and efficiency are essential elements. Because of their longer read ranges, they are also extensively employed in electronic toll collection and parking access control.
Again, for the purposes of this post, I will assume that a passive UHF tag is the best option for your unique application.
On what surface is the tag being applied?
We need to look more closely at the environmental variables that surround the RFID tag. For example, what type of surface will the RFID tag be placed to? Is it made of plastic, metal, glass, wood, or another material? Optimized performance is ensured by matching the proper inlay to the application surface.
In order to get an RFID tag to read on metal, you must use an on-metal RFID tag, in other words, an inlay specially designed to work on metal. Foam is the most commonly used standoff for many on-metal RFID tags. Glass is another surface for which users often optimize tag performance. In fact, there are some tags that perform better on glass than they do on plastics.
How long do you want the RFID tag to be functional? Will the RFID tag be exposed to chemicals, and if so, what type and how long will it be exposed? These types of inquiries will assist in determining what type of RFID tag construction is required to accomplish the intended output for your application while also ensuring the RFID tag survives the environmental conditions it will be subjected to. For example, if an application requires a tag to be exposed to the elements for five years, you should select materials that can withstand such circumstances, such as polyester, rather than paper, in the tag’s fabrication.