Chipless RFID reading system independent of polarization

One of the major drawbacks of chipless ultra-wideband (UWB) radiofrequency identification (RFID) systems is the polarization dependence. Most proposed tags have to be specifically oriented with the reader. This paper proposes a bistatic reading system which can rotate both the reader's emitting and receiving polarizations, by using two dual-access dual-polarization UWB antennas. The principle consists of electrically rotating the interrogating signal in transmission, while exploiting the rotation matrix in reception. By being able to rotate both polarizations, it is shown that cross-polarization chipless tags can be read independently of their orientation.