The tag, also known as the transponder (derived from the terms transmitter and responder), holds the data that is transmitted to the reader when the tag is interrogated by the reader. The most common tags today consist of an Integrated Circuit (IC) with memory, essentially a microprocessor chip. Other tags are chip less and have no onboard IC. Chip less tags are most effective in applications where simpler range of functions is all that is required; although they can help achieve more accuracy and better detection range, at potentially lower cost than their IC-based counterparts. From here on out, we will use the term tag to mean IC-based tag. We will refer to chip less tags explicitly, when needed.