Abstract
This chapter focuses on the concept of transmitting power without using wires that is also known as Wireless Power Transmission (WPT). This chapter attempts to present the most important and relevant works in this field of research in order to develop a topical ‘overview', present the current results, and also share some contributions and ‘vision' for the future. The technological developments in Wireless Power Transmission is also presented and discussed. The advantages, disadvantages, biological impacts and the most potential applications of WPT are also presented. This chapter presents also new and efficient designs of a rectifying antenna (rectenna) involved to be used at low and high input power levels constraints at microwave frequencies of ISM band in particular at 2.45 GHz and 5.8 GHz. The rectennas have been developed were based on microstrip technology incorporating a new class of phased antenna arrays with circular polarization associated with a new RF-to-DC rectifiers.
TopWireless Power Transmission Techniques
In the past few years, scientists have faced challenges involving power: the continuity of supplied power, recharging batteries, optimizing the location of sensors, and dealing with rotating or moving joints, and they are looking for alternate and efficient technologies to provide efficient electricity transfer. Although those challenges remain, new demands that arise from increased use of mobile devices and operation in dirty or wet environments. Where almost of these devices are powered by disposal batteries that they present many disadvantages such as: the need to either replace them or recharge them periodically and their big size and weight compared to high technology electronics, which mean that designers, engineers and researchers require new approaches and solutions to supplying power to equipment with cost effective, minimum losses and efficiently. In order to improve the ultimate electricity supply, Wireless Power transmission (WPT) has become a focal point as research point of view and nowadays lies at top 10 future hot burning technologies that are under research, these days.
Key Terms in this Chapter
Antenna Array: A geometrical arrangement of antenna elements with a deliberate relationship between their currents, forming a single antenna.
Wireless Sensors: A wireless sensors are standard measurement tools and a group of specialized transducers with a communications infrastructure for monitoring and recording conditions at diverse locations.
ISM band: The industrial, scientific, and medical radio band (ISM band),are also called unlicensed bands, refers to a group of radio bands or parts of the radio spectrum that are internationally reserved for the use of radio frequency (RF) energy intended for scientific, medical and industrial requirements rather than for communications. ISM bands are generally open frequency bands, which vary according to different regions and permits.
Rectenna: This term is derived from the fact that a rectenna is comprised of an antenna coupled with a rectifying circuit. This special type of antenna is used to convert electromagnetic energy into direct current (DC) electricity.
Energy Harvesting: Also known as power harvesting or energy scavenging is the process by which energy is derived from external sources such as solar power, thermal energy, wind energy, captured, and stored for small, wireless autonomous devices, like those used in wearable electronics and wireless sensor networks.
Wireless Power Transfer: Wireless power transfer (WPT) or wireless energy transmission is a collective term that refers to a number of different technologies for transmitting electrical energy from a power source to an electrical load without the use of discrete man-made conductors.
RFID: RFID (Radio Frequency Identification) is the automatic identification technology which uses radio-frequency electromagnetic fields to identify objects carrying tags when they come close to a reader.
Circular Polarization: Circular polarization of an electromagnetic wave is a polarization in which the electric field of the passing wave does not change strength but only changes direction in a rotary manner.