A.C.F. Reniers

Bio: A.C.F. Reniers is an academic researcher from Eindhoven University of Technology. The author has contributed to research in topics: Antenna (radio) & Parabolic reflector. The author has an hindex of 3, co-authored 4 publications receiving 191 citations.

Ambient RF Energy Scavenging: GSM and WLAN Power Density Measurements

Abstract: To assess the feasibility of ambient RF energy scavenging, a survey of expected power density levels distant from GSM-900 and GSM-1800 base stations has been conducted and power density measurements have been performed in a WLAN environment. It appears that for distances ranging from 25 m to 100 m from a GSM base station, power density levels ranging from 0.1 mW/m2 to 3.0 mW/m2 may be expected. First measurements in a WLAN environment indicate even lower power density values, making GSM and WLAN unlikely to produce enough ambient RF energy for wirelessly powering miniature sensors. A single GSM telephone however has proven to deliver enough energy for wirelessly powering small applications on moderate distances.

Fast prototyping of antenna and FSS structures

Abstract: A method for the fast creation of antenna and Frequency Selective Surface (FSS) prototypes is discussed. The method is suited for printed structures on planar and singly curved surfaces and avoids the use of photo-etching techniques. Furthermore, it allows for creating printed metallic structures on non-microwave-specific substrates. The method uses adhesive copper tape, common adhesive tape, a paper stencil, a ruler and a knife. The construction technique is first applied for creating a test structure, to be used with Vector Network Analyzer (VNA) measurements to determine the substrate's relative permittivity and loss tangent. The substrate characterization technique is discussed in detail and an example of the use is demonstrated. The prototyping technique is discussed in detail and practical hints are provided. Finally the construction of a microstrip array antenna and a RF energy harvesting FSS are discussed.

Representatives in the present case

Abstract: The present invention is directed to a living-being proximity sensing arrangement for a vehicle. The arrangement is arranged for distinguishing proximity of a human or animal body from proximity of a non-living object, and comprises a sensor unit including an antenna array, wherein the antenna array is operable in a plurality of operational modes for enabling use of said antenna array for performing at least one of a plurality of different electrical sensing techniques in each of said modes. The antenna array comprises means for providing an antenna input signal to said antenna array and means for presenting an antenna output signal from said antenna array, a plurality of patches spanning a first detection area of the antenna, and a plurality of interconnections between said patches. These interconnections are switchable for enabling connection and disconnection of said switchable electrical connections between said patches for enabling operation of said antenna in each of said plurality of operational modes.

Complex permittivity measurements with a low cost parabolic resonant cavity

Abstract: A low-cost Fabry Perot open resonator is used to measure the complex permittivity of flat sheets of dielectric materials in the X-band. The method is based on the measurement of the resonant frequency shift of the fundamental mode, described by the Gaussian beam theory. Instead of spherical mirrors, conventionally used for open resonators, the cavity is formed by parabolic reflectors, originally intended for satellite communications, reducing the production costs. A technique to improve the sample alignment is introduced, and to validate the results of the parabolic cavity, the relative permittivity and loss tangent of three different samples are measured.

Ambient RF Energy Harvesting in Urban and Semi-Urban Environments

Abstract: RF harvesting circuits have been demonstrated for more than 50 years, but only a few have been able to harvest energy from freely available ambient (i.e., non-dedicated) RF sources. In this paper, our objectives were to realize harvester operation at typical ambient RF power levels found within urban and semi-urban environments. To explore the potential for ambient RF energy harvesting, a city-wide RF spectral survey was undertaken from outside all of the 270 London Underground stations at street level. Using the results from this survey, four harvesters (comprising antenna, impedance-matching network, rectifier, maximum power point tracking interface, and storage element) were designed to cover four frequency bands from the largest RF contributors (DTV, GSM900, GSM1800, and 3G) within the ultrahigh frequency (0.3-3 GHz) part of the frequency spectrum. Prototypes were designed and fabricated for each band. The overall end-to-end efficiency of the prototypes using realistic input RF power sources is measured; with our first GSM900 prototype giving an efficiency of 40%. Approximately half of the London Underground stations were found to be suitable locations for harvesting ambient RF energy using our four prototypes. Furthermore, multiband array architectures were designed and fabricated to provide a broader freedom of operation. Finally, an output dc power density comparison was made between all the ambient RF energy harvesters, as well as alternative energy harvesting technologies, and for the first time, it is shown that ambient RF harvesting can be competitive with the other technologies.

Micropower energy harvesting

Abstract: More than a decade of research in the field of thermal, motion, vibration and electromagnetic radiation energy harvesting has yielded increasing power output and smaller embodiments. Power management circuits for rectification and DC–DC conversion are becoming able to efficiently convert the power from these energy harvesters. This paper summarizes recent energy harvesting results and their power management circuits.

Micropower energy harvesting

Abstract: More than a decade of research in the field of thermal, motion, vibration and electromagnetic radiation energy harvesting has yielded increasing power output and smaller embodiments. Power management circuits for rectification and DC-DC conversion are becoming able to efficiently convert the power from these energy harvesters. This paper summarizes recent energy harvesting results and their power management circuits.

RF Energy Harvesting and Transport for Wireless Sensor Network Applications: Principles and Requirements

Abstract: This paper presents an overview of principles and requirements for powering wireless sensors by radio-frequency (RF) energy harvesting or transport. The feasibility of harvesting is discussed, leading to the conclusion that RF energy transport is preferred for powering small sized sensors. These sensors are foreseen in future Smart Buildings. Transmitting in the ISM frequency bands, respecting the transmit power limits ensures that the International Commission on Non-Ionizing Radiation Protection (ICNIRP) exposure limits are not exceeded. With the transmit side limitations being explored, the propagation channel is next discussed, leading to the observation that a better than free-space attenuation may be achieved in indoors line-of-sight environments. Then, the components of the rectifying antenna (rectenna) are being discussed: rectifier, dc-dc boost converter, and antenna. The power efficiencies of all these rectenna subcomponents are being analyzed and finally some examples are shown. To make RF energy transport a feasible powering technology for low-power sensors, a number of precautions need to be taken. The propagation channel characteristics need to be taken into account by creating an appropriate transmit antenna radiation pattern. All subcomponents of the rectenna need to be impedance matched, and the power transfer efficiencies of the rectifier and the boost converter need to be optimized.

Energy Harvesting for Autonomous Wireless Sensor Networks

Abstract: Wireless sensor nodes (WSNs) are employed today in many different application areas, ranging from health and lifestyle to automotive, smart building, predictive maintenance (e.g., of machines and infrastructure), and active RFID tags. Currently these devices have limited lifetimes, however, since they require significant operating power. The typical power requirements of some current portable devices, including a body sensor network, are shown in Figure 1.