RFID Tag Choice Can Make or Break Your Passive UHF Tracking Project

RFID tag choice is critical to the success of your tracking project. There are many good, solid, money-saving, efficiency-making, data-rich, automagical reasons for using a passive ultra high frequency (UHF) RFID tracking system in your operations – none of which you will be able to realize if you choose the wrong RFID tag.

“In our project requirements discussions, we spend as much time determining what tag the customer needs as we do on multiple other components combined,” explains Richard Bissonnette, president of Strategic Systems and our resident RFID tag expert. “If you select a tag randomly or because you like the way it looks, but it doesn’t have enough memory or durability – just flat-out doesn’t meet the reality of what you’re trying to accomplish – your RFID project will fail, because the tag isn’t going to be able to get the job done.”

With an estimated 6.2 billion UHF RFID tags being sold in 2015, representing a 27 percent unit growth rate over 2014, the market is expanding, and new RFID tag form factors and capabilities are proliferating at an exciting pace. To help keep the options from overwhelming and derailing your project, we asked Rick to share his advice on the questions you need to be able to answer in order to ensure RFID tag-selection success. Here’s what he had to say.

Today’s tags are being purpose-built to perform best for specific environments and give you the best read results.

1. What are you trying to accomplish with your RFID tracking project?

“You need to nail down, as specifically as possible, what you want to accomplish with RFID, to determine whether or not RFID is even physically or budgetarily feasible for your project,” Rick says. “To say you want to do tool or parts tracking is one thing, and it sounds good. To specify that you want to track a bunch of individual metal parts jumbled together on top of each other in a box – where you’d be looking at lots of overlapping, individual, on-metal tags – then no, RFID is not going to be an inexpensive or even good solution. Now, tracking a box of items tagged with an RFID label as it moves through your warehouse, however, is a much less expensive, better fit.

“Just as important: How valuable are the items you want to track? Does the benefit of knowing where those items outweigh the cost of the technology required? The more specifically you know where the business value in your project lies, the better we can pinpoint your system needs.”

Takeaway: Know exactly what your end-goal is and how you envision that being accomplished – along with whether or not your needs allow for flexibility in how that goal may be achieved.

2. What items do you want to tag?

“You have to understand how the items you want to tag are going to handle RFID. One classic scenario where I have to break the bad news to people is this: someone wants to embed an inexpensive, passive UHF RFID tag between two pieces of aluminum or other metal as part of a manufacturing process. In that case, RFID tracking is never going to be the answer,” Rick says.

“What you are going to tag, the material the tag will adhere to, makes a difference. Because there are important limitations with passive UHF RFID. You cannot read these tags through metal or through liquids. It’s not all things to all people. ”

Takeaway: Remember that RFID is based on physics – energy and matter – so the composition of the items you want to track will definitely affect tag choice.

3. What are the environmental conditions of the area in which your RFID tracking will take place?

“Are the items you want to track subject to high humidity or being splashed by liquids?” Rick asks. “What about corrosive chemicals? Are they exposed to extremely high or extremely low temperatures? Do they go through a lot of shock and vibration, or other physically rigorous activities? Do you need an on-metal option or off-metal – because on-metal tags won’t work as well if they’re applied off-metal. These types of details will help determine the level of durability and form factor you’ll need in your tags, whether we’re looking at soft RFID labels or more hardened, industrial tags.

“There really is no such thing as a one-size-fits-all go-to tag, although there are families of go-to tags for different applications,” he continues. “Today’s tags are being purpose-built to perform best for specific environments and give you the best read results.”

Takeaway: RFID tag form factors are available at a wide range of price points, for meeting a variety of environmental conditions.

4. What read range do you need?

“Everybody wants a small tag with long range – it’s probably the single most wished-for tag people ask me about. They only have room for a 1” by 1” tag, but they want to read it from 40 feet away. And that’s something that physics just cannot deliver in an inexpensive, passive UHF tag. Generally speaking,” he explains, “with passive tags, the longer the read range, the bigger the antenna.

“Do you want to read items from a distance, like for identifying inventory in a warehouse, or is this a security or authentication application, where you’d want the tag to come into much closer contact with a reader before registering? Be ready to answer those types of questions, because read range definitely influences tag selection.”

Takeaway: A close read range for passive UHF RFID tags is generally less than 3 feet, while mid-range is between 3 and 9 feet, and long range is closer to 9 to 20 feet. While antennas and readers can be calibrated to different levels of sensitivity, tag read range cannot greatly outperform their physical limitations.

5. How much memory do you need on the tag?

“The type of application normally drives the memory requirement,” Rick explains. “Different types of tags have higher memory capacities than others. Every RFID tag, at its most basic, will allow you to assign an identification number to an item, and the reader will provide you with the information that that tag is read at the location that reader is in. High-capacity memory tags, however, can store more than just an identification number or product code. They can store things like model number, serial number, date of manufacture, manufacturing lot, manufacturing facility code, quality control station and so on. It all depends on what you need.

“Normally, folks look at high-memory tags for applications where they can’t easily access a database,” he continues. “So if I’m in a field and I need to know an item’s date of manufacture, I may want to have that information available directly from the tag. That’s when a tag can act like a portable database. And some tags will enable you to read and write or encode things like inspection dates right to the tag.

“So be sure to determine what information you really need to have on the tag, because every tag has a memory specification, just like your cell phone, and you can’t just buy any tag and put anything on it,” Rick cautions. “It’s the same as having a laptop with 128 gig of flash memory. When you need a terabyte, that 128 is not going to cut it.”

Takeaway: The type and amount of information you need from your tag directly affects your tag’s memory requirement. Passive UHF RFID tags can store between 128 bits and 8 KB of information. Keep in mind, too, that how you encode a tag – whether strings of identification numbers are okay or you want to have a combination of numbers, letters and special characters or words – using ASCII or hexadecimal encoding will use up different amounts of memory.

Active RFID and other sensor technologies have their own system and RFID tag choice considerations as well. To find out what technologies make the most sense for your RFID tracking application, contact us. We’re here to help.