The Myths of LF vs. HF

Another example involves a company that approached RFID Inc. last year, to develop an RFID system capable of reading and writing to one of two tags sunk flush into metal separated by mere millimeters. The company was willing to—and did, in fact—pay my firm more than half a million dollars for the manufacturing rights. It allocated resources and time toward the project that more than tripled that dollar amount, and then rolled the solution out product-wide into the surgical medical industry, as part of its high-integrity solution. This company (which cannot be named here for reasons of NDA) studied intently the RFID solutions on the market, in order to determine which was right for its particular application. The reasons should be obvious why we recommended—and why the company's management selected—LF over HF.

As for cost, back in the early to mid 1990s, HF was conceived in order to address applications of large tag volume, whereby the tags must be less expensive than LF tags—which, at the time, cost well above $1 apiece, but that does not mean LF can not compete today. If we are talking about a large volume of tags that are minimally packaged—call it an inlay, a substrate, a label form factor—then yes, facts are facts: LF necessitates a more costly hard-copper coil as a tag antenna, whereas HF can use fluid, ink or etching processes to create a cheaper antenna coil. But if the application calls for any packaging of some integrity—plastic, high-temperature materials, ABS—then the playing ground levels out, and LF can not only compete, but beat HF in pricing. In fact, an LF tag employing an EM Microelectronic EM4102 or equivalent read-only chip will beat the price of an HF tag with 2 kilobits of memory or more.

However, LF tags cannot compete with HF tags in certain applications, such as library books, smart cards or passports, all of which receive a great deal of press. Not much attention or press, on the other hand, is given to the fact that the high-volume tagging of beer kegs and LPG cylinders is typically accomplished with LF RFID.

Regarding standards, let's face it: In most applications, Americans simply don't care if a product is standard or not. The American thought process is that if a product can be made faster, cheaper and better, the public will not care about standards, but rather about performance and innovation. Yeah, that's right, I said it—standards can inhibit innovation. Just ask a rancher buying ISO 11784/5 animal ear tags for $3 to $5 apiece, when other markets enjoy a lower price for non-ISO-standard product.

Standards can be very necessary in terms of growing a market like supply chain visibility, (Wal-mart's and the U.S. Department of Defense's well-publicized initiatives, for example). But, if someone tomorrow were to invent a process involving 1-cent finished tags that could be read on liquid and metal without the need for spacing or backing materials, then EPC Gen 2 products would be tossed aside like day-old salad. However, I digress from what I mean to communicate, which is that just because HF RFID hardware may meet the ISO 15693 or ISO 14443 standard does not always mean the hardware is interchangeable between RFID vendors—and certainly not that they are equal in performance.