US Patent 7561107 RFID device with microstrip antennas

A Radio Frequency Identification (RFID) device such as an RFID tag according to one embodiment of the present invention includes first and second sides. A first microstrip antenna extends along the first side, the first microstrip antenna comprising a microstrip positioned towards the first side, a Radio Frequency-(RF-)reflective back plane, and a dielectric spacer positioned between the microstrip and the back plane. A second microstrip antenna extends along the second side, the second microstrip antenna comprising a microstrip positioned towards the second side, an RF-reflective back plane, and a dielectric spacer positioned between the microstrip and the back plane. The first and second microstrip antennas are each independently coupled to circuitry for receiving signals from the first and second microstrip antennas.