Glossary Of Rfid Terms -- F

Factory programming

Some read-only have to have their identification number written into the silicon microchip at the time the chip is made. The process of writing the number into the chip is called factory programming. This data can't be written over or changed.

False read

See phantom read.

Far-field communication

RFID reader antennas emit electromagnetic radiation (radio waves). If an RFID tag is outside of one full wavelength of the reader, it is said to be in the "far field." If it is within one full wavelength away, it is said to be in the "near field." The far field signal decays as the square of the distance from the antenna, while the near field signal decays as the cube of distance from the antenna. So passive RFID systems that rely on far field communications (typically UHF and microwave systems) have a longer read range than those that use near field communications (typically low- and high-frequency systems).

Faraday Cage

Also called a Faraday shield. Named after physicist Michael Faraday, a Faraday Cage is an enclosure formed of conductive material, or by a mesh of conductive material, that blocks out external static electrical fields and external electromagnetic radiation, if the conductor is thick enough and any holes in the mesh are significantly smaller than the radiation's wavelength. Faraday cages can provide effective electromagnetic shielding to prevent noise from interfering with the ability to read RFID tags, or to prevent RFID reader from interfering with other RFID devices.

Faraday Shield

See Faraday Cage.

Federal Information Processing Standards Publication 201

A United States federal government standard specifying Personal Identity Verification (PIV) requirements for federal employees and contractors. FIPS 201 was developed to satisfy the requirements of HSPD 12, approved by the Secretary of Commerce.

Field programming

Tags that use EEPROM, or non-volatile memory, can be programmed after it is shipped from the factory. That is, users can write data to the tag when it is placed on a product.

FIPS 201

A United States federal government standard specifying Personal Identity Verification (PIV) requirements for federal employees and contractors. FIPS 201 was developed to satisfy the requirements of HSPD 12, approved by the Secretary of Commerce.

Firmware

Coded instructions that are stored permanently in read-only memory. When upgrading a reader to read a new protocol, the firmware usually has to be changed. Some newer readers can be upgraded remotely over a network.

Fixed Reader

An RFID interrogator mounted to a wall, doorway, gate, table, shelf or other permanent or non-mobile structure, enabling employees to read the unique ID numbers of RFID tags attached to items in a warehouse or other setting along the supply chain.

FLASH

A special type of EEPROM that can be erased and reprogrammed in blocks instead of one byte at a time. It is usually written in capital letters, but it is not an acronym.

Fluidic Self-Assembly

A manufacturing process, patented by Alien Technology. It involves flowing tiny microchips in a special fluid over a base with holes shaped to catch the chips. The process is designed to mass assemble billions of RFID tags at very low cost.

Folded dipole

A dipole antenna in which the two poles are connected to each other, as well as to the microchip.

Foreign tag

A tag not associated with an item owned by a store or facility but which is nonetheless entering, leaving, or otherwise in the proximity of the store or facility and readable by RFID Readers located in the store or facility.

Form factor

The packaging a transponder can be put in. These include thermal transfer labels, plastic cards, key fobs and so on.

Forward channel

The path through which energy passes from the interrogator, or reader, to the RFID tag.

Free air

A term used to describe the reading of an RFID tag that is not attached to anything.

Frequency

The number of repetitions of a complete wave within one second. 1 Hz equals one complete waveform in one second. 1KHz equals 1,000 waves in a second. RFID tags use low, high, ultra-high and microwave frequencies. Each frequency has advantages and disadvantages that make them more suitable for some applications than for others.

Frequency hopping

A technique used to prevent readers from interfering with one another. In the United States, UHF RFID readers actually operate between 902 and 928 MHz, even though it is said that they operate at 915 MHz. The readers may jump randomly or in a programmed sequence to any frequency between 902 MHz and 928 MHz. If the band is wide enough, the chances of two readers operating at exactly the same frequency is small. The UHF bands in Europe and Japan are much smaller so this technique is not effective for preventing reader interference.

Frequency shift keying

A method of communicating data by switching between two slightly different frequencies.

FSK

See frequency shift keying