In this paper, we present a Transverse Electric (TE) polarized Bessel-beam antenna in the microwave range based on a leaky radial waveguide. According to the dispersion equation, an inductive sheet over a ground plane is needed. To achieve the inductive sheet, a grid structure printed on a dielectric substrate is designed. Besides, the radial waveguide is coaxially fed with a quasi-loop shaped structure to excite TE mode. The proposed antenna is investigated by simulation and measurement. In the measurement, a small loop is used to probe near magnetic field, and accurate measured magnetic intensity profiles are presented. The measurements show that TE-polarized Bessel beams can be launched within the non-diffractive range of 145 mm (2.803 λ0) at 5.8 GHz.
Sustainability in power electronics is a recent research topic. It takes place among current actions to grasp design choices that enable eco-design and circular economy in the domain. This paper shows the results and analysis of a literature review at the intersection of power electronics and sustainability without considering the reliability study of the power electronics systems. The first part explains the scope of the study. The second part shows a bibliometric analysis of the collected publications that underlines a pioneering position at the European level. The third part details the state-of-the-art and its analysis over four investigation topics which are: tools and methods, indicators, circularity and materials. This paper and the work behind are the results of collaboration at the French national level, as part of the workgroup CEPPS (Convertisseurs Electronique de Puissance Plus Soutenables—More Sustainable Power Electronics Converters) supported by the CNRS (Centre National de la Recherche Scientifique—French National Centre for Scientific Research) research group SEEDS (Systèmes d’énergie électrique dans leurs dimensions sociétales—Societal dimensions of electrical energy systems).
A novel rectifying circuit topology is proposed for converting electromagnetic pulse waves (PWs), that are collected by a wideband antenna, into dc voltage. The typical incident signal considered in this paper consists of 10-ns pulses modulated around 2.4 GHz with a repetition period of 100 ns. The proposed rectifying circuit topology comprises a double-current architecture with inductances that collect the energy during the pulse delivery as well as an output capacitance that maintains the dc output voltage between the pulses. Experimental results show that the efficiency of the rectifier reaches 64% for a mean available incident power of 4 dBm. Similar performances are achieved when a wideband antenna is combined with the rectifier in order to realize a rectenna. By increasing the repetition period of the incident PWs to 400 ns, the rectifier still operates with an efficiency of 52% for a mean available incident pulse power of -8 dBm. Finally, the proposed PW rectenna is tested for a wireless energy transmission application in a low-Q cavity. The time reversal technique is applied to focus PWs around the desired rectenna. Results show that the rectenna is still efficient when noisy PW is handled.
26 August 2014 in IEEE Transactions on Circuits and Systems I: Regular Papers
Power management of mobile digital systems-on-chip necessitates large voltage regulation performances. DC/DC converters used to supply digital cores are facing stringent constraints with respect to load transients, reference tracking and accuracy. The fast transient response offered by sliding-mode control is well suited to DC/DC converters with fast varying load. Fixed switching-frequency is also mandatory for EMI and noise related issues. Fixed-switching frequency sliding-mode control has been experimented as a multi-loop system. There is a necessity to investigate the stability when multi-loops interact and the parameter set for each loop is quite large. The paper details a methodology for the stability analysis of a frequency-controlled sliding-mode DC/DC converter. The proposed stability analysis takes the possible cross-interactions into account and can be used to optimise the DC/DC controller without the limitations of a non-interaction criterion. As a verification a DC/DC converter is implemented in CMOS 130 nm. Experimental results agree with the analysis main recommendations.