Patent ID: 8022827

Claim:
A tag orientation independent RFID tag system, comprising: a reader having a transmit antenna and operable to transmit a signal to an RFID tag; and, a tag orientation independent RFID tag including an omnidirectional circularly polarized antenna, said antenna providing a single lobe omnidirectional radiation pattern provided by a crossed Pair of dipoles tuned to the RFID frequency, each of said dipoles having a feed point, said crossed dipole antennas having a spiral configuration to minimize the area occupied by the crossed dipole antennas; and, a 90° delay line phase shifter between the dipole feed points for phase shifting the signal at one feed point by 90° relative to the other feed point such that said crossed dipoles establish an omnidirectional characteristic, whereby random orientations of the tag relative to the transmit antenna do not result in enough polarization mismatch loss to preclude communication between said reader and said tag; wherein said tag antenna includes a feed point having an interdigitated tine structure, and further including RFID microradio chips bridging across adjacent tines with opposite microradio chip ends connected to different adjacent tines.