When two waves (out of phase) impose on each other and the original signal is cancelled. Nulls are created s a result

Broadcasts the reader transmitter's RF signal into its surroundings and receives tag responses on the reader's behalf. Therefore - proper positioning of these (NOT THE READERS) is essential for good read accuracy

This type of antenna is largely unaffected by tag orientation - Preferred in system that uses high UHF or microwave frequencies in an operating environment where there is a high degree of RF reflectance (due to presence of metals and so forth)

RF energy radiates from antenna in linear fashion - Provide longest range - Sensitive to the orientation of tag - Has single E-field component - Can have a narrow beam pattern - Best for application with known tag orientation

Reader that can operate in different frequencies or can use different tag-to-reader communication protocols (generally stationary)

Frequencies between 30-300 KHz - Generally use passive tags - have low data-transfer rates from the tag to the reader - and are especially good if the operating environment contains metals - liquids - dirt - snow - or mud. Active tags also available

Die-cut web adhesive - paper face

An electronic signal or indicator - Audible alarms - strobes - light stacks - etc.

Image "burned" into photopolymer layer. All copper removed except where image was burned. Copper antenna goes through additional processes to protect from oxidation

The orientation of the transmitted electromagnetic field or the direction of oscillation of electromagnetically emitted waves

Readability of a tag greatly depends on this and the angle at which the tag is presented to the reader