Chipless RFID

RFIDs offer longer range and ability to be automated, unlike barcodes that require a human operator for interrogation.

RFID benefits from a very wide spectrum of functionalities, related to the use of radio-frequency (RF) waves for data exchange.

The acquisition of the identifier (ID) is made much easier and volumetric readings are possible, all on tags containing modifiable information.

The reasons for this enthusiasm are simple: barcode functions very well and is extremely cheap, the label as well as the reader.

It is also true that RFID contributes other significant functionalities, and the question is therefore one of imagining a technology based on RF waves as a communication vector that would retain some of the advantages of barcodes.

Pragmatically speaking, the question of system cost, and particularly of the tags that must be produced in large numbers, remains the central point.

Due to the presence of electronic circuits, these tags have a non-negligible cost that is a very great deal higher than that of barcodes.

The high cost of RFID tags is actually one of the principal reasons that chipped RFID is rare in the market for tags for widely distributed products, a market that numbers in the tens of thousands of billions of units sold per year.

However, technically speaking, chipped RFID offers significant advantages including increased reading distance and the ability to detect a target outside the field of vision, whatever its position.

The concept of chipless RF label has been developed with the idea of competing with barcodes in certain areas of application.

The barcode offers no other feature than the ID recovery; however, the technology is time-tasted, widespread, and extremely low cost.

For instance, the development of very low cost sensor - tags is now eagerly awaited for, for application reasons.

The tag demodulates this signal, processes the request, possibly writes data in its memory, and sends back a response, modulating its load.

They can be viewed as radar targets possessing a specific, stationary temporal or frequential signature.

In 2001, Roke Manor Research centre announced materials that emit characteristic radiation when moved.

The interrogator sends out a coherent pulse and reads back an interference pattern that it decodes to identify a tag.

[11][12][13] Flying Null technology uses a series of passive magnetic structures, much like the lines used in conventional barcodes.

The magnetic field created by the interrogator is such that it drives the soft material to saturation except when it is at the null volume.

[14][15] Surface acoustic wave devices consists of a piezoelectric crystal-like lithium niobate on which transducers are made by single-metal-layer photolithographic technology.

The reflections increase in size from nearest to farthest of the IDT to account for losses due to preceding reflectors and wave attenuation.