A. Takacs

Power source evaluation of a wireless power transfer system

With more than 230 products on store shelves and an estimation of 100 million wireless power devices in use by 2015 (IHS source), the wireless power market is rapidly growing. Moreover, current smartphones are used with several applications (music streaming, satellite navigation system or even NFC virtual key for car sharing) and thus a convenient power supply system is required. This paper addresses the complete modeling and characterization of this power source in a Wireless Power Transfer context by an original modeling approach. A good correlation between measurement and simulation is obtained both for electrical (e.g. input impedance, power, etc.) and electromagnetic (e.g. magnetic field) quantities. Through simulations performed on commercial softwares, the correlation simulation/measurement shows a difference of only 2% on the active power available on the load and the modeled behavior of the magnetic field corroborates with the measured one.

Ultra-compact Ku band rectenna

This paper addresses an innovative and ultra-compact rectenna designed for energy harvesting or wireless power transfer applications. The presented rectenna uses a printed cross dipoles antenna array and a rectifier implemented with only one silicon Schottky diode. Experimental results show that 1.15 mW of DC power can be obtained for an optimal load impedance of 500 Ω using a compact rectenna (2.5 cm2 or 0.6 square wavelength) illuminated by an electric field of 60 V/m at 14.7 GHz.

Compact rectenna for space application

This paper addresses an ultra-compact (2.8 cm2) and wide bandwidth rectenna operating in the extended Ku-band. Experimental results demonstrate that the proposed rectenna can harvest a DC power ranging from 0.125 mW to 1.43 mW for frequencies between 14.5 GHz to 19.5 GHz and for resistive loads between 250 Ω and 4 kΩ. A maximum conversion efficiency of 55.3 % is obtained at 16.05 GHz for an incident power density around of 1.26 mW/cm2. It is the first time, to the authors knowledge, that such high harvesting performances are obtained using an ultra-compact Ku-band rectenna.

Multiband rectenna for microwave applications

This paper reports recent results obtained in the Ku and K bands by using a multiband rectenna. The targeted application is the electromagnetic harvesting of the spill-over losses of microwave antennas for powering autonomous wireless sensors used for satellite health monitoring. The experimental results demonstrate that this compact rectenna can harvest efficiently the incident electromagnetic energy at three different frequencies that roughly correspond to the resonant frequencies of the used cross dipoles antenna array.

K-band energy harvesting for satellite application

This paper addresses the energy harvesting for powering autonomous wireless sensors on board of geostationary broadcasting satellites. The electromagnetic environment existing on such satellites is first investigated and the feasibility of energy harvesting by using microwave harvesting modules is discussed. The proof-of-concept experiment in K-band demonstrates for the first time the feasibility of such energy harvesting in satellite applications for powering autonomous wireless sensors.