Document Type
Thesis
Date of Award
9-30-1985
Degree Name
Master of Science in Electrical Engineering - (M.S.)
Department
Electrical Engineering
First Advisor
Edip Niver
Second Advisor
Stanley S. Reisman
Third Advisor
Peter Engler
Fourth Advisor
Robert R. Meola
Abstract
A frequency dependent analytical expression for the input impedance of a thin wire antenna is obtained using diakoptic theory. In diakoptic theory the linear antenna is seperated into electrically short segments where each segment is treated as a two-port network. This approach eliminates the need for an integral equation formulation. An impedance matrix is found which characterizes coupling between all segments. By expanding the free space Green's function in a power series in wavenumber k each entry in the resultant impedance matrix is obtained as a function of frequency. Enforcement of the continuity of currents and equality of scalar potentials at the nodes of the diakopted antenna yields a system of linear equations for the assembled structure. By solving for the input current the input admittance is found as a ratio of two polynominals in k. Equating the denominator of this expression to zero the poles of the radiating structure can be examined.
A systematic approach for the solution of the input admittance is achieved by assuming the unknown current vector to be expanded into a power series in k. By equating coefficients of like powers in k leads to a numerically efficient algorithm which is used to determine the input admittance as a function of frequency.
A computer code is developed which handles up to seven terms in the expansion of the impedances of the diakopted antenna. Generated data is compared with the input impedance obtained from a conventional integral equation solution. The data obtained from both methods is in good agreement with the existing results for low frequencies. Low order poles are also in good agreement with the reference solution obtained using the Singularity Expansion Method.
Recommended Citation
Smith, Howard Harold, "Frequency characterization of a thin linear antenna using diakoptic theory" (1985). Theses. 3474.
https://digitalcommons.njit.edu/theses/3474
