Developing a three-term improved circuit theory (ICT) algorithm and Computer-Aided design (CAD) for Co-Planar Dipole Array Antennas

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The use of antennas in wireless and satellite communication systems has necessitated antenna research in the area of the development and implementation of new efficient computational algorithms and other analysis techniques to aid in the design of antennas. The Improved Circuit Theory (ICT) method for multielement antennas is one of such analysis techniques. As a contribution towards the building of an advanced National Information and Communication Infrastructure (NICI) in Ghana, the study proposes an efficient ICT method of analyzing coplanar multielement wire antennas to aid in the design of antennas to support the NICL To achieve the proposed efficient ICT method, the conventional two-term ICT method was modified to include a third trial function to develop a Three-term ICT algorithm known as TTICT. A trial function analysis was carried out to select an appropriate third trial function from a list of known trial functions which together with the two Storer functions of the conventional ICT algorithm were used to derive two more elements of the new generalized input impedance matrix of the TTICT which is necessary for the implementation of the ICT method. For any length of the dipole elements of a parallel co-planar dipole arrays, these trial functions which are used in the current distribution equation of the ICT algorithm do not simultaneously vanish at the feed point thereby expanding the valid dipole elements lengths of a parallel co-planar array to arbitrary dipole elements lengths to which TTICT applies. TTICT was validated by applying it to analyze two parallel co-planar dipole arrays namely Yagi-Uda and Log-Periodic Dipole Arrays (LPDA). The accuracy of the results of the input impedance and the radiation characteristics computed with TTICT are n good agreement with those computed with the Method of Moment (MoM). Moreover, all the new formulas of the TTICT algorithm including the radiation pattern expression are expressible in closed form TTICT still presents an ICT algonthm that is superior in terms of computer running time and lesser storage space compared to MoM. TTICT algorithm thus provides a relatively very efficient method for the analysis of parallel co-planar dipole array antennas of arbitrary dipole elements lengths and would therefore be found useful in computer-aided design and computer-aided engineering (CAD/CAE) systems for the analysis of parallel co-planar dipole array antennas where response time is paramount.
A thesis presented to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirements for the award of Master of Science degree in Electrical Engineering, 2006