Increasing of Operation Range of System of RFID and Positioning

The presented paper is a part of large-scale investigations in a field of object (tag) identification and its positioning. The main attention is paid to distance-to-tag measurements in extended operation range, and the phase radio engineering system with homodyne signal conversion is proposed for implementation. Such a system can identify and localize several objects simultaneously. The system functioning assumes the tag operation in receiving and transmitting modes simultaneously and with very close frequencies, and each tag has its own shift frequency, which ensures its identifying. The problems of RFID system operation in extended operation range and mentioned conditions are discussed in the paper. Base equations of system operation are considered. One way of system link energy increasing is suggested. This approach assumes the use of one-port reflection transistor amplifier in transponder design. The simulation, design, and experimental study of one-port resonant transistor amplifier are considered. One-port amplifier consists of field-effect transistor and resonant circuit only. The amplifier gain is achieved by the use of positive feedback, which makes this reflection amplifier the regenerative one. Amplifier ensures excellent electrical characteristics: gain is about 30 dB and noise factor is about 5 dB. Mentioned signal amplification ensures adequate extending of system operation range. The design of amplifier is simplest. The amplifier power consumption is negligible. All of mentioned above makes described amplifier extremely useful in active transponder design during the implementation of system of radio frequency identification and object positioning.