Energy harvesting in low-power embedded system helps accelerate the growth of Internet of Things (IoT) applications such as smart home, wearable biotelemetry sensors, logistics surveillance, and machine-to-machine communications by extending the operational lifetime and reducing maintenance cost. Popular energy harvesting sources in IoT applications are mechanical movements, light, and heat since these energy sources are ubiquitous; an alternative source for energy harvesting in IoT devices is radio frequency (RF) energy. This research focus is on the RF rectifier; one of the most important blocks in micro- scale RF energy harvesting (RFEH) system. This thesis will cover the importance RF energy harvesting in IoT applications, the characterization and design trade-off of the two most widely used RF rectifier topologies, the input impedance characteristic of the on-chip Dickson topology RF rectifier, and the corresponding input impedance matching network design.