  Backscatter communication is a burgeoning low-power communication technology
that has been introduced into the Internet of Things (IoT) due to its excellent
self-sustainability. However, conventional backscatter communication (BackCom)
technologies often suffer from insufficient data transmission rates and are
difficult to meet the increasing bandwidth demands of Internet of Things
applications. In contrast, millimeter wave (mmWave) backscatter communication
holds great potential for high-speed data transmission because of its rich
spectrum resources. Therefore, this paper presents a comprehensive survey of
the existing literature on mmWave backscatter communications. Firstly, we
introduce the fundamental principles of mmWave backscatter communication,
including its architecture, basic techniques, and primer knowledge.
Subsequently, we review the various mmWave backscatter communication techniques
proposed in the current literature. We then discuss some applications based on
these techniques before finally addressing some challenges and open issues
associated with mmWave backscatter.
