Contents I. Introduction
Backscatter communications is considered as an enabling communication paradigm for Internet of Things (IoT) dut to its low cost and low energy consumption, and has been employed in various IoT scenarios, e.g., smart home [1], medical field [2], and bio-telemetry [3], etc.. A typical backscatter conmmunication system consists of the reader and the tag, in which the reader first transmit query signals to the tag, and then the tag modulate and reflect the query signals to the reader. Furthermore, from the perspective of the antenna configurations, backscatter communications can be classified into bistatic configuration and monostatic configuration. For bistatic configuration [4], the reader employs different antennas to transmit query signals and receive the backscattered signals. Instead, the reader employ the same antennas to transmit query signals and receive the backscattered signals for monostatic configuration [5].
