Application for spatial ASK modulation in UHF RFID transmitter based on digital metamaterial

The incompatibility of the cost and performance is a restrictive factor for the further development of RFID. In this paper, combining the latest development of digital metamaterial and RFID technology, a UHF RFID transmitter with spatial ASK modulation is proposed to reduce the complexity and the cost of radio frequency communication system equipment. The 1-bit digital metamaterial units based on polarization-insensitive Jerusalem cross structure form the 10×10 coding matrix. The proposed UHF RFID transmitter based on digital metamaterial inno-vatively realizes the spatial ASK modulation from -60° to 60° in azimuth plane. Finally, a preliminary communication system is built to test the performance of transmitter. The test result shows that the modulation depth of the spatial UHF RFID transmitter are all above 75%. The transmitter based on spatial ASK modulation provide a potential ability to solve the problem of missing tags in RFID system.