In this paper, a complete wireless power transmission scenario is presented, including an external transmission antenna, an in-body embedded antenna, a rectifying circuit, and a powered sensor. This system operates at the Industrial, Scientific, and Medical bands (902.8–928 MHz). For the antenna design, important parameters including reflection coefficient, radiation pattern, and specific absorption rate are presented. As for the rectifying circuit, a precise model is created utilizing off-the-shelf components. Several circuit models and components are examined in order to obtain optimum results. Finally, this work is evaluated against various sensors' power needs found in literature.

Advances in technology have seen mobile robots becoming a viable solution to many global challenges. A key limitation for tetherless operation, however, is the energy density of batteries. Whilst significant research is being undertaken into new battery technologies, wireless power transfer may be an alternative solution. The majority of the available technologies are not targeted toward the medium power requirements of mobile robots; they are either for low powers (a few Watts) or very large powers (kW). This paper reviews existing wireless power transfer technologies and their applications on mobile robots. The challenges of using these technologies on mobile robots include delivering the power required, system efficiency, human safety, transmission medium, and distance, all of which are analyzed for robots operating in a hazardous environment. The limitations of current wireless power technologies to meet the challenges for mobile robots are discussed and scenarios which current wireless power technologies can be used on mobile robots are presented.

The characteristic transfer parameters of inductive power transfer systems highly depend on the relative position of the coils to each other. While translational offset has been investigated in the past, the effect of rotatory offset on the transfer parameters is widely unclear. This paper contains simulation results of an inductive power transfer system with a rotatory offset in three axes and shows the possible improvements in the coupling coefficient. As a result, rotation angles can be used as control parameters and thereby increase the system efficiency. Alternatively, the allowed misalignment area of the secondary coil can be increased while maintaining the functionality and same dimensions.

Advances in material science and semiconductor technology have enabled a variety of inventions to be implemented in electronic systems and devices used in the medical, telecommunications, and consumer electronics sectors. In this paper, a wireless charging system is described as a wearable body heater that uses a chair as a transmitter (Tx). This system incorporates the widely accepted Qi wireless charging standard. Alignment conditions of a linear three-element coil arrangement and a 3 × 3 coil matrix array are investigated using voltage induced in a coil as a performance indicator. The efficiency obtained is demonstrated to be up to 80% for a voltage of over 6.5 Volts and a power transfer of over 5 Watts. Our results and proposed approach can be useful for many applications. This is because the wireless charging system described herein can help design seating areas for the elderly and disabled, commercial systems, consumer electronics, medical devices, electronic textiles (e-textiles), and other electronic systems and devices.

Here we demonstrate wireless energy transfer that exploits the conductivity and permittivity of soil to create a potential gradient on the surface around an earthed electrode, distributing electrical energy over the area. This generated surface potential can be amplified using a special standing-wave receiver for harnessing the distributed energy. We have experimentally mapped the surface potential around the electrode and plotted the received energy covering an area of 1200 m2. Key operating parameters are determined with a discussion on optimizing the system efficiency. This technique could address the challenge of distributing electrical energy to many low power devices over large outdoor areas without the use of wires.

A method of power transmission is proposed that delivers power through the resonance of a helical receiver with its surrounding stray capacitance. The system operates in a quasi-wireless state where power is transferred over a single connection to a surface much larger than the dimensions of the receiver. This ensures high-efficiency energy transfer over large areas without the need of strong coupling electromagnetic fields. Standard power connectors such as tracks, plugs, and cords may be easily replaced with conductive surfaces or objects such as foil sheets, desks, and cabinets. Presently, the method is experimentally demonstrated at the small scale using loads of up to 50 W at an efficiency of 83% with both bare and insulated surfaces. Simple circuit modeling of the system is presented which shows close agreement with experimental results.