Wireless charging is a technology of transmitting power through an air gap to electrical devices for the purpose of energy replenishment. The recent progress in wireless charging techniques and development of commercial products have provided a promising alternative way to address the energy bottleneck of conventionally portable battery-powered devices. However, the incorporation of wireless charging into the existing wireless communication systems also brings along a series of challenging issues with regard to implementation, scheduling, and power management. In this paper, we present a comprehensive overview of wireless charging techniques, the developments in technical standards, and their recent advances in network applications. In particular, with regard to network applications, we review the static charger scheduling strategies, mobile charger dispatch strategies and wireless charger deployment strategies. Additionally, we discuss open issues and challenges in implementing wireless charging technologies. Finally, we envision some practical future network applications of wireless charging.

Wireless Charging Technologies: Fundamentals, Standards, and Network Applications

We propose a compact planar ultrawideband (UWB) antenna with 3.4/5.5 GHz dual band-notched characteristics. The antenna consists of a beveled rectangular metal patch and a 50 Omega coplanar waveguide (CPW) transmission line. By etching two nested C-shaped slots in the patch, band-rejected filtering properties in the WiMAX/WLAN bands are achieved. The proposed antenna is successfully simulated, designed, and measured showing broadband matched impedance, stable radiation patterns and constant gain. An equivalent circuit model of the proposed antenna is presented to discuss the mechanism of the dual band-notched UWB antenna. A UWB antenna and a single band-notched one are also provided for references.

A Compact Ultrawideband Antenna With 3.4/5.5 GHz Dual Band-Notched Characteristics

This paper presents a novel broadband rectenna for ambient wireless energy harvesting over the frequency band from 1.8 to 2.5 GHz. First of all, the characteristics of the ambient radio-frequency energy are studied. The results are then used to aid the design of a new rectenna. A novel two-branch impedance matching circuit is introduced to enhance the performance and efficiency of the rectenna at a relatively low ambient input power level. A novel broadband dual-polarized cross-dipole antenna is proposed which has embedded harmonic rejection property and can reject the second and third harmonics to further improve the rectenna efficiency. The measured power sensitivity of this design is down to $- {\bf 35}\;{\bf dBm}$ and the conversion efficiency reaches 55% when the input power to the rectifier is $- {\bf 10}\;{\bf dBm}$ . It is demonstrated that the output power from the proposed rectenna is higher than the other published designs with a similar antenna size under the same ambient condition. The proposed broadband rectenna could be used to power many low-power electronic devices and sensors and found a range of potential applications.

A High-Efficiency Broadband Rectenna for Ambient Wireless Energy Harvesting

Reactive matching is extended to wide bandwidths using the impedance property of LC-ladder filters. In this paper, we present a systematic method to design wideband low-noise amplifiers. An SiGe amplifier with on-chip matching network spanning 3-10 GHz delivers 21-dB peak gain, 2.5-dB noise figure, and -1-dBm input IP3 at 5 GHz, with a 10-mA bias current.

A 3-10-Ghz low-noise amplifier with wideband LC-ladder matching network

With the development of wireless communication technology, the need for bandwidth is increasing continuously, and the growing need makes wireless spectrum resources more and more scarce. Cognitive radio (CR) has been identified as a promising solution for the spectrum scarcity, and its core idea is the dynamic spectrum access. It can dynamically utilize the idle spectrum without affecting the rights of primary users, so that multiple services or users can share a part of the spectrum, thus achieving the goal of avoiding the high cost of spectrum resetting and improving the utilization of spectrum resources. In order to meet the critical requirements of the fifth generation (5G) mobile network, especially the Wider-Coverage , Massive-Capacity , Massive-Connectivity , and Low-Latency four application scenarios, the spectrum range used in 5G will be further expanded into the full spectrum era, possibly from 1 GHz to 100 GHz. In this paper, we conduct a comprehensive survey of CR technology and focus on the current significant research progress in the full spectrum sharing towards the four scenarios. In addition, the key enabling technologies that may be closely related to the study of 5G in the near future are presented in terms of full-duplex spectrum sensing, spectrum-database based spectrum sensing, auction based spectrum allocation, carrier aggregation based spectrum access. Subsequently, other issues that play a positive role for the development research and practical application of CR, such as common control channel, energy harvesting, non-orthogonal multiple access, and CR based aeronautical communication are discussed. The comprehensive overview provided by this survey is expected to help researchers develop CR technology in the field of 5G further.

Full Spectrum Sharing in Cognitive Radio Networks Toward 5G: A Survey

This paper presents a comparative study on the resilience to load variations brought by combining structures for amplifier topologies. Three out-of-phase four-way combining topologies based on Wilkinson combiners, 90° and 180° hybrid couplers are compared with a conventional in-phase four-way combining topology based on Wilkinson combiners. An experimental evaluation is conducted using a load-pull bench for the characterization of printed circuit board (PCB) demonstrators operating at 2.45 GHz with a VSWR up to 5:1. Measurement results point out the superiority of the out-of-phase combining topologies providing reduced performance variations under load pulling. It is demonstrated that these topologies have a higher resilience to unpredictable load variations, with reduced gain, efficiency, and output power variations. For all the considered out-of-phase combining demonstrators, the gain variation is reduced by more than 1.5 dB at 1 dB compression point compared to the conventional in-phase combining demonstrator.

Active VSWR Robustness Comparison for Different Phase Combining Topologies

This paper presents a multilayer phase shifter topology taking advantage of the air-filled substrate integrated waveguide (AFSIW) technology in the context of multilayer. By properly choosing the dimensions of this type of phase shifter, no additional transition is needed for matching purpose. Also, thanks to the AFSIW multilayer feature, a self-compensating effect is obtained, which allows realizing an equal-length configuration. For demonstrations, a phase shifter with a relative phase shift of 44.17 ± 5.64° is validated in measurement over the entire Ka-band. In this frequency range, an amplitude imbalance of −0.13 ± 0.44 dB is obtained. Nevertheless, the experiment validates the broadband responses with a return loss better than 11.33 dB. The proposed phase shifter structure allows realizing high-performance phase shifters without increasing the fabrication complexity.

Self-matching Self-compensating Air-filled Substrate Integrated Waveguide (AFSIW) Phase Shifter

The present invention relates to an assembly for propagating waves of frequencies comprised between 1 GHz and 10 THz. According to the invention, this assembly comprises: (a) a waveguide (11, 21) forguiding said waves, said waveguide (11, 21) being made from a plastic, one portion of said waves propagating in the interior of this waveguide (11, 21) and another portion of said waves propagating onthe exterior of this waveguide (11, 21); and (b) a protective jacket (12) that encircles said wave guide (11, 21) while defining one or more spaces between said waveguide (11, 21) and said jacket, wherein said waves propagating on the exterior of said waveguide (11, 21) are contained, said protective jacket (12) thus forming a barrier protecting the latter from external interference.

Assembly for propagating waves of frequencies comprised between 1 GHz and 10 THz

Conception et Miniaturisation des antennes pour les tags RFID UHF passifs, Conférence invitée

Dans cet article, nous presentons une facon ludique d’enseigner les communications numeriques et la conception d’antennes en ecole d’ingenieurs. Par l’intermediaire de radio-logicielles, nous proposons aux etudiants du departement Telecommunications de l’ENSEIRB-MATMECA d’appliquer leurs cours de communications numeriques, traitement du signal, codage de canal, etc. sur des signaux reels. Concretement, nous les guidons par l’intermediaire d’un manuel de Travaux Pratiques (TP), a decoder les trajectoires des avions en demodulant des signaux Automatic Dependent Surveillance-Broadcast (ADS-B). Outre le cote ludique de ce projet, traiter des signaux reels permet egalement de veriﬁer certaines hypotheses de modelisations comme le caractere blanc et gaussien du bruit ou encore la non-selectivite en frequence du canal perturbant les signaux ADS-B. Aﬁn d’ameliorer les performances de detection des algorithmes developpes par les etudiants du departement Telecommunications, un groupe d’etudiants du departement Electronique a en charge la modelisation et la conception d’une antenne patch ADS-B.

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Anthony Ghiotto

Papers

Active VSWR Robustness Comparison for Different Phase Combining Topologies

Self-matching Self-compensating Air-filled Substrate Integrated Waveguide (AFSIW) Phase Shifter

Assembly for propagating waves of frequencies comprised between 1 GHz and 10 THz

Conception et Miniaturisation des antennes pour les tags RFID UHF passifs, Conférence invitée

Simulation d’un émetteur / récepteur ADS-B et décodage temps réel à l’aide : de MATLAB, d’une radio logicielle et d’une antenne patch