LINEAR ARRAYS: CURRENTS, IMPEDANCES, AND FIELDS, II.
HARVARD UNIV CAMBRIDGE MASS CRUFT LAB
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A new solution is presented for the problem of determining the radiation pattern and driving-point impedances of an array of N parallel, in-line elements curtain array. An approximate solution is found in terms of simple trigonometric functions. This solution is obtained from Hallens integral equation in terms of two separate distributions a distribution of transmitting type as for an isolated antenna, and a distribution of receiving type to represent the induced currents. This analysis differs from the conventional theory, since it is not necessary to assume identical current distributions on each antenna. Two separate cases are considered Case I for specified base currents, and Case II for specified base voltages. As an example, the three- and four-element arrays with full wavelength elements and quarter-wave spacing between elements are investigated. For Case I with the main beam in the endfire position, a large discrepancy is found between the actual results and the conventional theory. However, it is found that by specifying the base voltages as in Case II, the conventional results are almost completely recovered. The effect on the element currents and impedances due to element interaction is given for the complete range of beam position angles for a three-element array. The variation of the element currents and impedances is easily interpreted with the new theory. Author
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- Numerical Mathematics