The work presented in this paper concerns the modeling of an integrated transformer in monolithic technology for high frequencies containing coils of planar type and magnetic circuit made of several layers of materials. Circular, square, and polygonal shapes of the planar coils are the important difference regarding transformer topologies. In this work, we have chosen the stacked octagonal form of coils. The transformer will be integrated into a converter of type flyback. We have opted for the Wheeler method and the S-parameters for determining the geometrical and the electrical parameters. The electrical π model presented summarizes perfectly the various parasitic effects generated by stacked layers of different materials constituting the transformer. The electromagnetic simulation, by using COMSOL Multiphysics 4.3 software, illustrates the current density and the distribution of magnetic field lines. We have also used software PSIM 6.0, to validate the equivalent electrical circuit of the transformer in flyback converter.

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Modeling and simulation of an integrated octagonal planar transformer for RF systems

This paper presents the conception, fabrication and characterization of integrated inductors containing magnetic layers. We require different steps of micro-technologies: preparation of glass and ferrite substrates, RF sputtering, photolithography, etching and finally electroplating techniques for copper and gold films. The geometrical magnitudes are determined by using HFSS simulator software. The measurements performed at low and high frequencies (up to 1 GHz) permit to verify the correlation between experiment and simulation results. The inductance of the manufactured spiral inductor is about 200 nH and it is constant from low frequency up to 0.9 GHz.

http://aemjournal.org/index.php/AEM/article/download/47/pdf

Design, Manufacturing and characterization of integrated inductors with magnetic layers for DC-DC converter

A simple model is designed for an inductive immunosensor in which the magnetic particles are attached to the bioreceptors to form a sandwich on the surface of an inductor. The inductor consists of a coil covered on a silicon oxide wafer. The coil comprises 250 turns of a planar gold wire, which is approximately 200 nm thick and 392 mm long, placed in a circle with a diameter of 2 mm. The model is well characterised by controlling the geometrical and electrical parameters and also the permeability of the magnetic material. To evaluate the feasibility of the model for virus monitoring, a novel inductive immunosensor is designed and for the first time applied for the detection of hepatitis B surface antigen (HBsAg). At first, Fab′ segment of primary anti-HBsAg is immobilised on the coil. Then, the coil is exposed to HBsAg and the complex is introduced to a secondary antibody conjugated with magnetic particles to form an immune-sandwich. Finally, the influence of magnetic particles on the coil inductance is recorded and used as a signal for HBsAg detection. The magnetic inductive immunosensor showed specific responses toward HBsAg with the detection limit of 1 ng mL−1, linear range of 1 to 200 ng mL−1, and a sensitivity of 6 × 10−4 mL ng−1. The experimental results showed a very good agreement with simulation data indicating the compatibility of sensor sensitivity to the expected theoretical values.

Designing a magnetic inductive micro-electrode for virus monitoring: modelling and feasibility for hepatitis B virus.

This article concerns the development, the fabrication and the characterization of integrated inductors using magnetic layers for use in power electronics. Properties of inductors were extracted using an electrical model which takes into account eddy current. Inductors with one and two magnetic layers were fabricated with thicknesses varying between 100 and 500 µm. Measurements carried out with a Vector Network Analyzer up to 350 MHz are presented. The results show that the use of one magnetic layer allows the inductance of the coreless inductor to be multiplied by two and an inductor with two magnetic layers allows the inductance of the coreless inductor to be multiplied by 15 for 500 µm magnetic thickness layers.

Fabrication and properties of integrated magnetic inductors using an RLC model which takes into account eddy current

Limited available space and some other system requirements for the integration of magnetic components address the importance to improve their overall performance and reduce losses. This article evaluates the performance of planar inductor with Moore fractal design. The inductor is modeled using partial inductance method, where each segment is divided into a certain number of elementary filaments, and then, mutual inductances between filaments are calculated. A developed simulation tool is used for the analysis of high-frequency parameters (equivalent inductance, equivalent resistance, and quality factor), taking into account parasitic effects. The proposed model is verified by measurements and electromagnetic simulations. Two planar fractal inductors, with different segment widths, 2.9 and 3.6 mm, are examined. A good agreement between the results obtained by modeling, measurements, and electromagnetic simulations is achieved. The main advantage of the proposed simulation tool is that it can be easily modified and applied for the modeling and optimization of various inductor geometries, which will be useful in future research.

Modeling and Performance Analysis of Planar Fractal Inductors

Design of a new electrical model of a ferromagnetic planar inductor for its integration in a micro-converter

This paper presents the design and modeling of planar inductor and transformer for their integration in a Forward converter. The windings are of octagonal spiral planar topology. Basing on Wheeler method, we evaluate the inductance values of planar coils. All parasitic effects generated by stacking of different material layers are summarized perfectly in the π-electrical model of both on chip inductor and transformer. The electromagnetic simulation, by using COMSOL Multiphysics 5.3 software, illustrates the distribution of magnetic field lines, the current density and the temperature distribution in our integrated micro coils. To validate the different geometric and electrical parameters values, we have simulated the circuit of the Forward converter containing the π-electrical circuit of on chip integrated inductor and transformer, using the software TINA 9.0.

Design and Modeling of Octagonal Planar Inductor and Transformer in Monolithic Technology for RF Systems

The work presented in this article concerns the design of micro-transformer in Monolithic Technology for High Frequencies comprised of planar type coil and a magnetic circuit made of several layers of materials. This microtransformer will be integrated into a micro-converter of type Fly-back. The Mohan method for determining the geometric parameters and the use of S-parameters for the calculation of technological parameters was chosen. The electrical model in $\pmb{\pi}$ presented, perfectly summarizes the various parasitic effects generated by stacking layers of different materials constituting the micro-transformer. The study of electromagnetic effects allowed us to show the role of ferrite, which is used to confine the magnetic field lines and minimize disruption of the neighbor ship. To validate dimensioning of the geometrical and technological parameters, we have simulated with the help of the software PSIM6.0, the equivalent electrical circuit of the converter containing the electrical circuit of the dimensioned planar micro-transformer.

Modelling and Simulation of the Micro Transformer for Power Electronics

The main aim of this paper is to present the new design of an integrated planar spiral inductor with a new structure of an underpass to obtain a high inductance, high quality factor and minimum losses into winding and magnetic core. The performance of this structure dependent on the geometrical, electrical parameters and material properties. These parameters are calculated at 350 MHz and this is the high frequency used for MEMS applications. Furthermore, thermal analysis in inductor from finite difference method is described. The heat transfer model is based on heat conduction and heat convection. Moreover, the heat source is calculated by different losses. In addition, the simulation results from 3D finite element method using software also been presented in this paper. It is based on both the classical heat equation and certain condition limits. However, a new design of an underpass has been proposed where a via is fabricated with a circular layer. The input and output of the spiral are implanted in the same direction. In addition, the magnetic core is the solution to decrease the temperature. Finally, the results of the finite difference method are compared with simulation results from finite element method. The good agreement between the results is obtained. The proposed via and a core magnetic are responsible for enhancement the thermal behavior in integrated inductor. The result shows that the temperature of the air core inductor and magnetic core inductor could be 53 °C and 33 °C, respectively.

/pdf/design-for-integrated-planar-spiral-inductor-for-mems-1lssw3r1.pdf

Mokhtaria Derkaoui

Papers

Design of a new electrical model of a ferromagnetic planar inductor for its integration in a micro-converter

Modeling and simulation of an integrated octagonal planar transformer for RF systems

Design and Modeling of Octagonal Planar Inductor and Transformer in Monolithic Technology for RF Systems

Modelling and Simulation of the Micro Transformer for Power Electronics

Design for Integrated Planar Spiral Inductor for MEMS