Antenna Array Theory Research Articles

The fractal random array

A novel method of random array synthesis is presented. This new method relies on the application of the underlying self-similarity inherent in random fractals to the problem of antenna array theory. Several examples demonstrate the synthesis procedure and its usefulness in producing robust, low sidelobe arrays.

Theory and applications of antenna arrays

Theory and applications of antenna arrays

Book review - Theory and application of antenna arrays

Book review - Theory and application of antenna arrays

Theory and Application of Antenna Arrays. M. T. Ma. Wiley-lnterscience, Chichester, 1974. 413 pp. £12.60.

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Book reviews - The theory and design of circular antenna arrays

Book reviews - The theory and design of circular antenna arrays

A New Log-periodic Structure with Asymmetric Dipole Elements

In this communication an approximate analysis of a new log-periodic structure made of asymmetric dipole elements is presented. A simple mathematical expression for the radiation pattern has been derived using the concept of conventional linear antenna array theory. Theoretical calculations have been made and the plots of E- and H-plane patterns have been given for various values of ψ, the separation angle between the two halves of the LPD antenna. An effort has also been made to show the variation of the radiation pattern for various values of asymmetry ratio AR.

Investigations on the Non-planar Log-periodic Antenna, having Tilted Dipoles

This paper presents theoretical and experimental investigations on the non-planar log-periodic dipole antenna, whose upper and lower halves contain dipoles, inclined by angles α1 and α2 respectively. Using the fact that a tilted dipole is capable of receiving horizontally as well as vertically polarized signals, it is mathematically shown that the utility of the log-periodic dipole antenna (LPDA) can be increased by tilting the constituent dipoles. Using the linear antenna array theory, the expressions for the far field radiation patterns, power gain and aperture, are derived. Calculations were made to predict the effect of Ψ (angle between the two halves of the LPDA) and the tilt angles (α1, and β2) of the dipoles on the radiation pattern, power gain and aperture of the non-planar log-periodic dipole antenna. Comparison is made between the theoretical and experimental results. It is concluded that both the results agree reasonably.

A mathematical theory of antenna arrays with randomly spaced elements

Various probabilistic properties of a large antenna array with randomly spaced elements have been studied. It is found that for almost all cases of practical interest the required number of elements is closely related to the desired sidelobe level and is almost independent of the aperture dimension, the resolution (or the beamwidth) depends mainly on the aperture dimension, and the directive gain is proportional to the number of elements used if the average spacing is large. As a consequence the number of elements required is considerably less than that with uniform spacings. Starting with a given number of elements and a given aperture size, it is possible to improve the resolution by a factor of ten, a hundred, or more by spreading these elements over a larger aperture with little risk in obtaining a much higher sidelobe level and a lower directive gain. In fact, this method offers a solution which is optimum in a certain statistical sense, i.e., all sidelobes are of equal level with equal probability. In addition, this analysis also gives a simple estimate of the sidelobe level of most nonuniformly spaced antenna arrays. In a number of such arrays studied by various investigators with high speed computers, the agreement found is remarkable.

The theory of a single-ring circular antenna array

The single-ring circular antenna array of axial dipoles is analyzed in this paper. Such an array consists of m parallel dipoles, equally spaced on the circumference of a circle whose radius is ρ. The two principal properties with which a designer is concerned are (1) the radiation pattern and (2) the impedance of each element in an array, both of which can be found if the current distribution along the element is known. To synthesize a specified radiation pattern, the voltages at the center of each element must be determined.