Includes a title page in Arabic

Thesis (Ph.D.) Doctoral Egypt - Japan University of Science and Technology (E-JUST) - School of Electronics , Communications and Computer Engineering (ECCE) - Electronics and Communications Engineering (ECE) Department 2024

Includes bibliographical references

Sensor nodes are used to monitor a wide variety of environmental properties (ie., tempera-ture , pressure , and humidity) Furthermore , they are an essential component in the development of smart cities Regularly replacing the battery is essential to maintain the node's performance For sensors located in remote or hazardous locations , this is deemed a critical concern Further more , due to the growing number of IoT devices , the replacement of billions of non-functional and dangerous batteries becomes expensive and environmentally undesirable An encouraging substitute for a sustainable Wireless Sensor Network (WSN) and Internet of Things (IoT) is the Radio Frequency (RF) energy obtained from the surrounding environment The energy obtained from harvesting RF energy can be stored in supercapacitors to directly supply power to the node or recharge the battery These wireless sensor networks would be capable of carrying out their sensing tasks and wireless communication autonomously , without the need for monitoring , configuration , or maintenance RF energy scavenging can be achieved by collecting ambient waves or by using a dedicated transmitter This dissertation focuses on the gathering of energy from ambient RF waves The sustained presence of cellular and Wi-Fi communication waves , unaffected by factors such as time , weather , location , and human movement , makes them a robust source for energy har-vesting This thesis presents the development and evaluation of antennas and rectifying circuits specifically designed for the purpose of capturing ambient RF energy Firstly , an integrated rectenna with a small size and high efficiency is introduced for oper-ation in the 2.45 GHz frequency spectrum An analysis is conducted to compare two rectifier topologies and determine the advantages of eliminating the matching network from the ree-tifier An impressive rectifier conversion efficiency of 74.1% has been attained A unique omni-directional antenna with a high gain of 3.72 dBi and a compact dimension of 25 mm x 29 mm is designed and built to finalize the rectenna system The same antenna is utilized in conjunction with a reflector to boost the gain to around 8.3 dBi

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