Pulse shaping for backscatter radio

Backscatter radio is being increasingly used for identification, sensing, and localization. The increased number of pervasive IoT systems that utilize backscatter radio as a low-power and low-cost communication scheme has led to dense deployments of tags that need to operate under bandwidth constraints. However, typical backscatter radio modulators perform switching “on-off” operation and modulate data with rectangular pulses, which are known to occupy an extensively wide bandwidth. This work derives new techniques and demonstrates front-ends that control the tag reflection coefficient over time in a continuous manner, thus enabling the generation of arbitrary backscattered waveforms and reduced bandwidth occupancy. The principles presented hereby will enable sophisticated tags to perform more complex modulation schemes, while maintaining the RF front-end complexity at low levels, using a single PIN diode or FET.