Surface and Underground Water Level Monitoring Using Wireless Sensor Node with Energy Harvesting Support

In this paper development and testing of a wireless sensor node that is powered by solar energy harvesting is described. Implemented wireless sensor node is characterized by low cost and consumption, long mean time between maintenance, simplicity, flexibility, modularity and miniature design in applications for monitoring of environmental parameters. As a replacement for relatively expensive battery supply and in order to minimize maintenance costs, energy harvesting solution that uses a miniature solar panel and supercapacitor is tested. This node is used for measurements of water levels of surface and underground waters for application in agriculture. For this purpose the node is expanded with a capacitive sensor for measurement of water levels, which is particularly discussed in this paper as simple and innovative solution

Analysis of the Coupling Effect in Different Meander-Type Winding Planar Transformers

International audienceIn this paper, planar printed-circuit board (PCB) transformers with different winding arrangements are presented. Three different arrangements of the primary and the secondary meander-type windings are designed and fabricated. The electrical parameters of the transformers for all three designs are analyzed and compared. A significant increase of inductance of the primary and the secondary winding is achieved with an appropriate meander-type winding arrangement. In the frequency range of interest, the inductance is approximately 145 nH for the first design, whereas the inductance is approximately 1250 nH for the second and the third design. The coupling coefficient is 0.14 for the first design, whereas it is around 0.9 for the second and the third design. The transformer of the proposed design is to be used in low-power DC/DC converters; therefore, the core with high permeability Ferroxcube 3C90 was chosen. In addition, the transformers of the same winding arrangements were tested with Ferroxcube 3F3 core

Design, Modeling, and Analysis of a Compact Planar Transformer

International audienceThis paper presents a new design of a planar transformer. Over the surface of a flat core, meander-type design was engraved, so that symmetrically adjusted primary and secondary coils, of the same meander-type, can fit into the engraved design. Primary and secondary coils were covered with another flat core consequently forming a compact planar transformer. Windings of primary and secondary coils are printed on both sides of PCB. Conductive stripes of a winding from upper and bottom layer are connected by vias. The transformer was analyzed when the primary and secondary coils were without a core and with a core. High frequency parameters of the transformer were obtained by finite element modeling software and Impedance Analyzer HP4194A in the frequency range from 50 kHz to 1 MHz. The transformer is intended to be used in DC-DC converters (for switching frequency up to several hundred kHz)

High-performance zig-zag and meander inductors embedded in ferrite material

This paper describes the design, modeling, simulation and fabrication of zig-zag and meander inductors embedded in low- or high-permeability soft ferrite material. These microinductors have been developed with ceramic coprocessing technology. We compare the electrical properties of zig-zag and meander inductors structures installed as surfacemount devices. The equivalent model of the new structures is presented, suitable for design, circuit simulations and for prediction of the performance of proposed inductors. The relatively high impedance values allow these microinductors to be used in high-frequency suppressors. The components were tested in the frequency range of 1 MHz–3GHz using an Agilent 4287A RF LCR meter. The measurements confirm the validity of the analytical model. r 2005 Elsevier B.V. All rights reserved

Improved Performance of Multilayer CPW Inductors on Flexible Substrate

In this paper, we present the modeling, fabrication, measurement techniques, and characterization results of multilayer miniature coplanar waveguide (CPW) meander-type inductors for high-frequency applications. Detailed procedure of the fabrication process based on using ink-jet printing technology is given. Silver nanoparticle ink that contains 20 wt% of silver was printed on a flexible polyimide foil 50 mu m thick in one, two, and three layers. It is shown that multilayer CPW inductors have improved performance. Almost two times better Q-factor value was achieved. This is an encouraging result for multilayer printing in ink-jet technology