Backscatter communication is a wireless communication paradigm wherein devices transmit information by reflecting or modulating incident radio frequency (RF) signals from ambient sources or dedicated transmitters, rather than actively generating RF signals. This concept investigates energy-efficient data transmission techniques for energy-constrained or battery-free devices, focusing on the design of low-power hardware, signal processing for decoding weak reflected signals, and its application in domains like ubiquitous sensing, passive identification, and the Internet of Things, leveraging its key characteristics of minimal power consumption and reliance on external RF power.