A new design is presented for a wideband orthogonal interconnect between two perpendicular printed wiring boards, employing novel geometries and materials to minimize stress under cyclic loading. This will ensure fatigue survivability in high vibration environments, opening the door to vertical interconnection in RF circuit design. This is, to the best of knowledge, the first complete design and prototype for an orthogonal interconnect at the board level for broadband RF circuits. An analytical approach is used to define the driving parameters in the stress distribution within a smooth curve joining two perpendicular surfaces using analytical geometries, and Finite Element Analysis is used to finalize the design and ensure all constituent materials in the interconnect are subjected to stresses below their fatigue strength at 10 million cycles at full deflection. A manufacturing process is then proposed using thermoforming to shape the Liquid Crystal Polymer base material into the desired geometry, as well as an assembly solution to mount the interconnect to an RF signal feed card. Finally, a test setup is designed allowing for high cycle fatigue testing within the order of hours, including the capability to monitor performance of the interconnect by tracking DC continuity through a simulated application using a single post design. The prototype interconnect is tested to failure and is shown to survive 18 million cycles of a typical loading application before failure of the LCP springs occurs in the mode predicted by the initial FEA model.

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

No description available.

No description available.

A research report submitted to the Faculty of Science, University of the Witwatersrand, in partial fulfillment of the degree of Master of Science. / The Toeplitz form is a most useful and important teo! in many areas of applied. mathematics today including signal processing, time-series analysis and prediction theory. It is even used in quantum mechanics in Ising model correlation functions. (Abbreviation abstract) / AC 2018

The classical moment problem concerns distribution functions on the real line. The central feature is the connection between distribution functions and the moment sequences which they generate via a Stieltjes integral. The solution of the classical moment problem leads to the well known theorem of Favard which connects orthogonal polynomial sequences with distribution functions on the real line. Orthogonal polynomials in their turn arise in the computation of measures via continued fractions and the Nevanlinna parametrisation. In this dissertation classical orthogonal polynomials are investigated rst and their connection with hypergeometric series is exhibited. Results from the moment problem allow the study of a more general class of orthogonal polynomials. q-Hypergeometric series are presented in analogy with the ordinary hypergeometric series and some results on q-Laguerre polynomials are given. Finally recent research will be discussed.

Bibliography: leaves 154-158.

The dielectric waveguide component has become a mature industry in these days in making it and understanding how it works. There are many theoretical and numerical methods to solve these waveguide modes. For example, the rigorous vectorial coupled transverse mode integral equation formulation (VCTMIE), finite-difference frequency-domain method (FDFD), vectorial beam propagation method (VBPM) and modal expansion method with simple bases (MEMSB)¡Ketc. With the exception of the MEMSB method and the alike, all these methods work very hard to handle interface boundaries and many require many terms meet the convergence requirements. In this thesis, we propose a rigorous modal expansion method based on a set of orthogonal transverse magnetic bases to analyze arbitrarily profiled 2-D cylindrical dielectric waveguides. First, we expand the mode field solution of a general multi-layered waveguide by linear combination of 1D homogeneous solutions. Magnetic and components are chosen for its continuity property across the material interface. The choice of Magnetic field over electric field also reduces the number of terms and minimizes the Gibb¡¦s phenomenon. Our new vector bases eliminate the numerical difficulty of working with the singular term of the cylindrical differential operators. When compared with the results using simple bases, we further reduce one quarter of terms without loosing any accuracy. Although the process of deriving the formulation of this vector cylindrical basis expansion technique is complex because Bessel functions and their derivatives are involved, the resulting matrix eigenvalue-eigenvector equation is much simpler than that of the simple bases and the new the result is also more accurate. We also extended the analysis to study the 2-D cylindrical dielectric waveguide problem.

The purpose of this thesis is to develop a set of tracking systems for Multiple Persons on DSP-Based. There are three sub-systems in our tracking system, including ¡§Moving Object Detection¡¨, ¡§Contour Matching¡¨ and ¡§Ellipse Algorism¡¨. First of all, the system utilizes CCD camera to capture the image which we want to control, and then detects the moving object from the continuous image array. If the system detects an invador, it will make the position of this invador with the coordinate projection, and then lock the invador's head to track. Finally, the tracking system marks the coordinate separately and exports it in LCD. From the results of the experiment, this system does meet the expectation and obtain good performance and strong robustness.

Abstract Wideband-CDMA (WCDMA) is a kind of third-generation wireless communication system. It can provide multi-rate services and fast transmission with wideband technology. To improve the solution of no enough wireless bandwidth currently, the 3G communication systems have been researched and developed in several leading countries recently. WCDMA adopts a kind of new spreading codes named Orthogonal Variable Spreading Factor codes (OVSF codes) that have advantages of dynamically variable rates and keeping orthogonality. OVSF codes can provide different data transmission rates by assigning codes with different lengths. By building a code tree, we can discuss some better schemes to assign available data rate. In this paper, we propose an efficient channel assignment scheme that can decrease the call blocking rate and complexity of channel reassignment procedure. Based on the properties of the binary code tree, we use code merge scheme to decrease channel reassignment rate and call blocking rate. This will efficiently improve the performance of channel assignment and spectral efficiency. Simulation results show that the proposed scheme has expected results.