A BPSK Backscatter Modulator Design for RFID Passive Tags

An integrated circuit implementation of a BPSK backscatter modulator for passive radio frequency identification (RFID) transponders has been carried out. The design is based on a combination and modification of earlier techniques. The modulation technique that has been used in this study is binary phase shift keying (BPSK). This kind of modulator provides modulation in an ultra high frequency (UHF) wave band along with significantly low power dissipation. Furthermore, the topology of the developed modulator allows us to control its output resistance so that only a minor fraction of the active power at the antenna propagates to the modulator. In the circuit development process, the cost and the size of the modulator has also been taken into consideration. The development of the modulator circuit is simulated in computer aided design software, P-SPICE. An efficient modulator has been achieved in the UHF band after optimization of the circuit components in a carefully investigated circuit design. This design also shows the minimum power dissipation of around 7.52 times 10^-11 W, as a result of optimization and minimization of the circuit size.