The Internet of Things (IoT), by collecting, processing, and uploading information from its surroundings, makes the preliminary base for the construction of a smart city. To utilize IoTs fully, establishing wireless sensor networks (WSNs) as a subset technology of the system is pivotal. Among all energy sources, the radio frequency energy, with its extensive coverage, easy accessibility, and characteristic of being free of spatial limitations, is the optimal choice for energy harvesting [1]. This project aims to conduct a thorough investigation on a wideband wireless energy harvester with high efficiency and verify its application prospect in portable power sources. I have comprehensively studied and modeled the components of a wireless energy harvesting system. I further fabricated the wireless energy harvester based on the optimized circuit diagram. It successfully featured a high sensitivity of 2701 V/W at 1.05 GHz or a wide bandwidth ranging from 0.5 GHz to 2.5 GHz. Finally, I used the devised sensor in real-life scenarios and successfully powered a thermos hygrometer and a LED. I built a network of multiple energy harvesters with an in-situ monitoring system, analogous to the IoT. In this work, I have proposed a methodology to fabricate wireless energy harvesters with high sensitivity and wide bandwidth. This research will bridge the gap between the scientific exploration for novel devices and their application in real-life scenarios.