Introduction

The items that you need to identify and track are tagged with, well, tags. So, a tag is the better half of the RFID system because it contains information about the item to which it is attached and has the capability to provide that information on request. A tag makes it to the item in three steps: The tag with the basic functionality is manufactured, the tag is turned into a label, and the label is placed on the item. From your perspective, this process involves the following facts:

• All the tags are composed of the same basic components because they offer the same basic functionality: to help identify and track an item.

• To meet the varied needs of different applications, tags come in different forms, shapes, and sizes.

• Tags must be properly placed on items so that they could be easily read by readers.

So, the main goal of this chapter is to understand the role of a tag in an RFID system. To accomplish this goal, we will explore three avenues: tag components, tag types, and tag placement.

Understanding Tags

Generally speaking, RFID is a means to identify an object using radio frequency transmission, which suggests that communication is involved in the identification process. The communication takes place between a reader and a tag. A tag, attached to an item that needs to be tracked, contains identification and possibly more information about the item. For example, in a supply-chain system, a tag may contain...