Meaning
Radio waves hitting a passive tag are reflected and modulated to transmit data without the need for an active transmitter on the device. RF backscatter allows sensors and identification labels to operate using only the energy harvested from an external reader. This technology is the foundation of most modern supply chain tracking systems.
Reflection Modulation
Varying the impedance of the antenna changes how much of the incoming signal bounces back. During rf backscatter, the tag toggles its internal state to create a pattern that the reader interprets as binary data. This process requires almost no power compared to traditional radio transmission.
Power Efficiency
Energy for the internal logic comes from the rectifying circuit that converts the reader’s signal into a small DC voltage. Because rf backscatter eliminates the battery, the tags can be thin enough to embed in a paper sticker. The lifespan of the device is limited only by the durability of the substrate.
It allows for the deployment of thousands of sensors in a single facility without the maintenance burden of replacing power cells.
Read Range
Distance between the tag and the antenna is the primary factor limiting the reliability of the data link. Signal strength drops off rapidly, making rf backscatter suitable for proximity applications or gated warehouse entries. Metallic surfaces and liquids in the environment can absorb the energy and prevent a successful read.
