RFID system utilizing parametric reflective technology
A system and method for encoding and decoding information by use of radio frequency antennas. The system includes one or more interrogator devices and RFID data tags. The RFID data tags include a plurality of antenna elements which are formed on a substrate or directly on an object. The antenna elements are oriented and have dimensions to provide polarization and phase information, whereby this information represents the encoded information on the RFID tag. The interrogator device scans an area and uses radar imaging technology to create an image of a scanned area. The device receives re-radiated RF signals from the antenna elements on the data tags, whereby the data tags are preferably represented on the image. The re-radiated RF signals preferably include polarization and phase information of each antenna element, whereby the information is utilized using radar signal imaging algorithms to decode the information on the RF data tag.
1. A method for reading data stored in an RF data tag, the method comprising:
transmitting electromagnetic radiation at a predetermined polarization to a scanned area, wherein a chipless and passive RF data tag in the area having an antenna element with polarization and phase parameters re-radiates electromagnetic radiation;
receiving the re-radiated electromagnetic radiation from the RF data tag;
determining the polarization and phase parameters of the antenna element from the received electromagnetic radiation; and
converting the polarization and phase parameters into data representative of information encoded in the RF data tag.
2. The method of claim 1 wherein determining further comprises calculating elevation and azimuth compression data from the polarization and phase information to identify the RF data tag.
3. The method of claim 1 wherein determining further comprises performing a signal image processing algorithm to the received electromagnetic radiation to calculate the polarization and phase characteristics.
4. The method of claim 1 further comprising producing an image of the scanned area in which the electromagnetic radiation is transmitted and received, wherein the antenna element is present in the image.
5. The method of claim 1 wherein the re-radiated electromagnetic radiation of the RF data tag is received while the RF tag is moving.
6. The method of claim 1 further comprising varying frequency of the transmitted electromagnetic radiation.
7. The method of claim 1 wherein transmitting is performed from a plurality of separate transmitting and receiving sites which are synchronized.
8. The method of claim 1 further comprising discriminating between spatially adjacent antenna elements from the received electromagnetic radiation.
9. The method of claim 1 wherein the receiving of the re-radiated electromagnetic radiation from the RF data tag is in the far field.
10. The method of claim 1 wherein the receiving of the re-radiated electromagnetic radiation from the RF data tag when the RF data tag at least 3 meters away.