Simplifying and size reduction of Kaiser-Koch multiband fractal arrays using windowing and quantization techniques

Abstract

Fractal arrays are known for their self-similar performance in multi-band operation. A large number of elements in the array is a source of inconvenience in the realization procedure. In this paper, a technique is introduced for the simplification and size reduction of the Koch array. The fractal array factors presented keep the same shape at several bands because they are constructed from self-similar curves. A Kaiser window as a generating pulse function is proposed for the design of Koch-array factors. Kaiser windows are characterized by having the lowest side lobes of all windows in the transformed domain. Applying such a technique would result in an array current distribution having lower side lobes, with a reduced array size after setting a threshold beyond which the elements are eliminated. The resulting reduced array is then quantised for implementation purposes. This paper also compares the performance of reduced Koch arrays for multiband operation with their derivative Koch arrays.