Ip, Wei Chi. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 92-94). / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.ii / Acknowledgement --- p.iii / Table of Content --- p.iv / Lists of Figures --- p.vii / Lists of Tables --- p.xii / Chapter Chapter 1: --- Introduction --- p.1 / Chapter 1.1 --- Research Motivation and Obj ective --- p.1 / Chapter 1.2 --- Original Contribution --- p.2 / Chapter 1.3 --- Overview of the Thesis Organization --- p.3 / Chapter 1.4 --- "Research Approach, Assumptions and Limitations" --- p.4 / Chapter Chapter 2: --- Power Divider Design Fundamentals --- p.5 / Chapter 2.1 --- Power Divider Basics --- p.5 / Chapter 2.2 --- Wilkinson Power Divider --- p.6 / Chapter 2.3 --- Power Divider with Unequal Power Division --- p.8 / Chapter 2.4 --- Multi-way Power Divider --- p.9 / Chapter 2.4.1 --- Wilkinson N-way Hybrid --- p.10 / Chapter 2.4.2 --- Radial Hybrid --- p.11 / Chapter 2.4.3 --- Fork Hybrid --- p.12 / Chapter 2.4.4 --- Multi-layer Approach --- p.IS / Chapter 2.4.5 --- Power Recombination Concept --- p.15 / Chapter 2.4.6 --- Multi-coupled-line Approach --- p.18 / Chapter Chapter 3: --- Conventional Power Divider Designs with Harmonic Suppression --- p.20 / Chapter 3.1 --- Resonating-stubs Topology --- p.20 / Chapter 3.2 --- Asymmetric Defected Ground Structure (DGS) --- p.26 / Chapter 3.3 --- Anti-Coupled Line Structure --- p.30 / Chapter 3.4 --- Microstrip Electromagnetic Bandgap (EBG) Based Topology --- p.32 / Chapter 3.5 --- Embedded Resonators Topology --- p.37 / Chapter 3.6 --- Extended Line Approach --- p.39 / Chapter Chapter 4: --- New 2-way Power Divider Design with Spurious Suppression and Impedance Transformation --- p.41 / Chapter 4.1 --- Proposed Topology --- p.41 / Chapter 4.2 --- Design and Analysis --- p.42 / Chapter 4.3 --- Simulation Study --- p.45 / Chapter 4.4 --- Experimental Verification --- p.50 / Chapter 4.5 --- Summary --- p.57 / Chapter Chapter 5: --- New 2-way Power Divider Design with Extended Spurious Suppression --- p.58 / Chapter 5.1 --- Proposed Topology --- p.58 / Chapter 5.2 --- Design and Analysis --- p.59 / Chapter 5.3 --- Simulation Study --- p.64 / Chapter 5.3 --- Experimental Verification --- p.68 / Chapter 5.4 --- Summary --- p.71 / Chapter Chapter 6: --- New 2-way Unequal Power Divider Design with Dual-harmonic Rejection --- p.72 / Chapter 6.1 --- Proposed Topology --- p.72 / Chapter 6.2 --- Design and Analysis --- p.73 / Chapter 6.3 --- Simulation Study --- p.76 / Chapter 6.4 --- Experimental Verification --- p.77 / Chapter 6.4 --- Summary --- p.80 / Chapter Chapter 7: --- New 3-way Power Divider Design with Multi-harmonic Rejection..… --- p.81 / Chapter 7.1 --- Proposed Topology --- p.81 / Chapter 7.2 --- Design and Analysis --- p.82 / Chapter 7.3 --- Simulation Study --- p.85 / Chapter 7.4 --- Experimental Verification --- p.87 / Chapter 7.4 --- Summary --- p.90 / Chapter Chapter 8: --- Conclusion --- p.91 / References --- p.92 / Author's Publications and Awards --- p.95 / Chapter Appendix 1: --- ABCD Parameters of Some Useful Two-port Circuits --- p.96 / Chapter Appendix 2: --- More Designs of Proposed Configuration in Chapter 5 --- p.97 / Chapter A2.1 --- Miniaturized version of Example 1 --- p.97 / Chapter A2.2 --- Design with improved stop-band response --- p.101 / Chapter A2.3 --- Design of prototype with 2 GHz operating frequency --- p.104 / Chapter Appendix 3: --- Brief Summary of Power Dividers with Harmonic Suppression --- p.108

The first study of magnetohydrodynamic (MHD) equilibria and external kink modes in shaped plasmas on the High Beta Tokamak - Extended Pulse (HBT-EP) is described. A new poloidal field coil and high-current, low-voltage capacitive power supply was designed and installed. The new coil significantly modifies the shape of the plasma cross section and provides a new research tool for the study of kink mode structure and control. When fully energized, the coil creates a magnetic separatrix, which defines the boundary between confined and unconfined plasma. The separatrix is set by a poloidal field null called an “X-point”, which is on the inboard side of the torus, above the midplane. Several arrays of magnetic sensors observe and characterize the plasma equilibrium and the MHD fluctuations from kink modes. Free-boundary plasma equilibria are reconstructed using standard methods that minimize the mean-square error between the numerically reconstructed equilibria and various measurements. Reconstructions of shaped plasma equilibria show the creation of fully diverted plasmas with shaped outer boundaries. The reconstructions are confirmed by direct measurements using arrays of magnetic sensors and a moveable Langmuir probe to measure the outermost closed flux surface. Measurements of individual kink modes are obtained from the magnetic fluctuations using a technique known as biorthogonal decomposition. External kink modes that naturally arise in shaped plasmas are observed and described. The poloidal structure of modes in shaped plasmas are found to be similar to those that arise in circular plasmas, except near the X-point. The magnetic signature of kink modes on the surface of the plasma are calculated using the ideal MHD code DCON. For plasmas with an X-point, DCON shows a short-wavelength, low amplitude structure near the X-point. The code VALEN is used to calculate the perturbed magnetic field measured at the sensors due to the DCON mode at the plasma surface. VALEN includes the effects of sensor/plasma separation and eddy currents induced in conducting structures by rotation of the modes. Good agreement is found between the measured mode structures and the ideal kink mode structures calculated at the sensors by VALEN. A distributed array of forty active control coils was used to perturb the plasma equilibria, and for both shaped and circular equilibria, the structure of the response to the perturbation was found to be the same as the that of the dominant naturally occurring mode in that equilibrium. Finally, the magnitude of the plasma’s response to applied magnetic perturbations was found to be comparable between shaped and unshaped plasmas, even though separation between the sensors and the boundary of the shaped plasmas increases relative to circular plasmas with the same plasma current and radial positions. In addition to demonstrating a new research tool for study of kink modes on HBT-EP, this research demonstrates the importance of accurate electromagnetic calculations, including eddy currents, when comparing measured and predicted mode structure.

Thesis (Ph.D.)--University of Nevada, Reno, 2005. / "August, 2005." Includes bibliographical references (leaves 74-75). Online version available on the World Wide Web.

A new second order accurate nonuniform grid spacing technique which does not depend on supraconvergence is developed for Finite Difference Time Domain (FDTD) simulation of general three dimensional structures. The technique is useful for FDTD simulations of systems which require finer details in small regions of the simulation space by providing the ability to utilize nonuniform grid spacing. The stability conditions of the new technique are derived and shown to be consistent with uniform grid formulation and the accuracy of the technique is investigated and shown to be second order. The advantage of the new technique is that it allows for greater simulation detail while reducing the computational and memory requirements compared to the current uniform grid FDTD techniques. Additionally, the derivation of the expressions associated with the inclusion of material properties in the FDTD simulation with nonuniform grids is presented allowing for the development of a nonuniform FDTD simulator for general lossy 3D systems associated with on and off chip interconnects, electronic packages and microwave circuits. In order to illustrate the utility of this simulator, time domain electromagnetic simulation of a 3-D lossy interconnect structure associated with a generic surface mount IC package is presented. The time domain currents and fields are computed in the structure to investigate ground bounce, signal degradation, and crosstalk associated with the interconnects and packaging structure. The supply plane conductivities are included in the simulation allowing the observation of the current densities in the power/ground planes as a function of time. Finally, the FDTD simulation tool is proposed and used as a Virtual TDR (V-TDR) to extract the circuit models associated with complex 3D structures. The time domain response of a multiport structure is used to extract the equivalent circuit parameters to characterize the multiport by using the multiport time domain reflection (TDR) based general deconvolution algorithm. Examples of coupled interconnects and transmission lines are presented to illustrate this technique. / Graduation date: 1997

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 103-109).

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 165-173). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--Washington State University. / Includes bibliographical references.

Two kinds of computational electromagnetics (CEM) methodology are discussed for the challenges in integrated circuit (IC) and printed circuit board (PCB) design. One is an extension of Cagniard-de Hoop method that provides analytic time-domain expressions for the field constituents, making up some drawbacks of numerical techniques that would lose power in super-high frequency simulation or extreme fine structure. A modeling of line-source excited by electromagnetic pulse is analyzed for a thin sheet with high-contrast dielectric and conductive properties. The response of reflection and transmission to the power exponential pulse and the power exponential monocycle pulse are studied using this newly proposed method consequently as a benchmark for practical design. The other method focuses on improving the broadband accuracy of the mixed-form fast multipole algorithm (MF-FMA) by applying rotation techniques. Coordinate system rotation with rotation matrix and pseudo-spectral projection rotation based on fast Fourier transform (FFT) are discussed. Through rotation, translation matrices become very sparse, which enables us to save storage as well as the CPU time. Either of them has certain advantages depending on the number of harmonics used. Hence, increasing the number of multipoles in the low frequency regime to shift up the transition region of MF-FMA can be feasible to improve the overall accuracy significantly. Numerical results of inter connector and sphere with large number of unknowns are given to certify the effectiveness of rotation methods. / published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

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