Antenna Design Considerations For RFID Applications

While the RFID concept has been around for decades, recent reductions in the size and cost of integrated circuits (ICs) have greatly expanded the range of feasible applications for this technology. Unlike ICs, however, antennas have not kept pace with Moore's law in terms of cost and size. As a result, antenna and sensor technology is a limiting factor for RFID today. The requirements of reader and tag antennas are not unlike those for many communication systems -- driven by applications and regulations. In this article, we discuss both factors and recommend some novel antenna options for RFID systems.

RFID applications

The RFID concept works as follows. A reader transmits a signal that is received by an antenna integrated in a small RF chip. In general, the chip is activated only when an RFID reader scans it. When the chip wakes up, it sends the unique identifier number, which the reader passes along to applications such as inventory control and shipping.

There are many potential applications for RFID, the most obvious being a more robust replacement for bar codes. However, innovative companies regularly find new applications for the enhanced range, capacity, and read-write capability of RFID systems. Readers can be big enough for forklifts to pass through or small enough to fit on retail shelves. Retail, in fact, holds the most potential among RFID applications. In this space, there are four retail applications that hold the potential for greatly reducing overhead. They are: conveyer belt systems, warehouse inventory, forklift systems, and smart shelves.