D.Ing. / Changes in the preferred technologies used in modem switched mode power supplies are driven by the need for a decrease in cost of manufacturing while maintaining the highest possible power density. Modem materials allow smaller components to be manufactured without affecting their electromagnetic properties but thermal problems still impair efforts to further reduce their size. Increased switching frequencies cause increased conductor and core losses in magnetic components such as inductors and transformers. Amongst other advantages the increased surface area of low-profile planar structures allow better removal of the heat generated in the component and this work reevaluates conductor optimization for specific planar inductor windings. Conductor optimization has been a topic thoroughly investigated over the last few decades and these techniques have been adopted for planar winding design. It will be shown that the process involved in the manufacturing of helical planar windings allows further exploitation of the basic optimization process. A per-layer optimization technique, earlier proposed by other researchers and deemed impractical at the time, is revised and it is shown here that it can be successfully implemented in the chosen winding type. The per-layer optimization is also extended to accommodate non-sinusoidal current waveforms in this work. Other facets of loss reduction are also addressed. Windings are shaped in the region of air gaps in magnetic circuits to reduce the losses caused by the fringing flux intersecting the conductors but since the shaping influences both the ac-resistance and dc-resistance of the winding an optimization process is required to find the optimal conductor arrangement. Contributions are made with regard to speeding up the process of finding the optimal layout of conductors around the air gap by devising a simple model for the flux distribution of the fringing flux. The effect of combining the per-layer optimization technique with these shaping techniques is exploited to its full potential in this work and contributes largely to loss reduction in helical inductor windings carrying currents containing ac- and dc components. The optimization time is reduced by allowing winding shaping while maintaining the dc-resistance of each layer. The optimal winding shape then becomes a function of the window constraints for a chosen core rather than finding it through conventional methods. Case studies, complete with FEM-simulations and experimental measurements, are offered in support of the proposed solutions. Manufacturing issues are dealt with and loss measurement techniques developed as part of this work.

In high-frequency circuit design, performance is often limited by the quality of the passive components available for a particular process. Specifically, spiral inductors can be a major bottle-neck for Voltage-Controlled Oscillators (VCOs), Low-Noise Amplifiers (LNAs), mixers, etc. For designers to correctly optimize a circuit using a spiral inductor, several frequency-domain characteristics must be known including the quality factor (Q), total inductance, and the self-resonant frequency. This information can be difficult to predict for spirals built on lossy silicon substrates because of the complicated frequency-dependent loss mechanisms present. The first part of this research addresses the need for a scalable, predictive model for obtaining the frequency domain behavior of spiral inductors on lossy silicon substrates. The technique is based on the Partial Element Equivalent Circuit (PEEC) method and is a flexible approach to modelling spiral inductors. The basic PEEC technique is also enhanced to efficiently include the frequency dependent eddy-currents in the lossy substrate through a new complex-image method. This enhanced PEEC approach includes all of the major non-ideal effects including the conductor-skin and proximity effects, as well as the substrate-skin effect. The approach is applied to octagonal spiral inductors and comparisons with measurements are presented. To complement the scalable enhanced-PEEC model, a new wide-band compact equivalent circuit model is presented which is suitable for time-domain simulations. This model achieves wide-band accuracy through the use of "transformer-loops" to model losses caused by the magnetic field. A fast extraction technique based on a least squares fitting procedure is also described. Results are presented for a transformer-loop compact model extracted from measurements. The combination of an accurate scalable model and a wide-band compact equivalent-circuit model provides a complete modelling methodology for spiral inductors on lossy silicon. / Graduation date: 2003

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 97-106). Also available on the World Wide Web.

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

No description available.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Abstract. Vita. Also available via the Internet

Thesis (MS)--Montana State University--Bozeman, 2008. / Typescript. Chairperson, Graduate Committee: James P. Becker. Includes bibliographical references (leaves 147-148).

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 50-54). Also available on the World Wide Web.

Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Prof. Rao Tummala; Committee Member: Prof. G.K. Chang; Committee Member: Prof. Maysam Ghovanloo.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references. Also available in electronic version.