Broadband Array Integrated Approach To Research

The synthesis of unequally spaced arrays is mainly discussed in this thesis. Firstly, Simulated Annealing(SA), which is capable of searching optimal results globally, is applied to the synthesis of unequally spaced arrays. SA is used to optimize the locations and feed current distribution of linear arrays. The synthesized array shows good scanning ability and has a broad bandwidth. SA is also effective in the thinning of arrays. The thinned array pattern is favorable, but its broadband performance is limited. Then an approach to the synthesis of aperture-shared arrays is presented. The synthesized arrays can perform well in a wide bandwidth, but the beamwidth of any array is somewhat different when its operating frequency changes.Secondly, the synthesis of two typical fractal arrays, which are Cantor linear array and Sierpinski planar array, are discussed. These two kinds of arrays show good wideband property when the array size is large, but the peak sidelobe levels (PSLL) of the array patterns are a little high. Then a self-similar fractal radiation pattern synthesis method for reconfigurable multiband arrays is introduced. This method is based on a generalised Fourier series synthesis approach, and a basic array is scaled and shifted to achieve a wideband array. An approach to the synthesis of fractal arrays based on SA is also presented. Arrays synthesized by these two kind of methods own excellent broadband property, and their patterns have low sidelobes.Thirdly, the application of cyclic difference sets(CDS) to the synthesis of thinned arrays is introduced. The array pattern synthesized by CDS is remarkable, and shows good wideband performance. The synthesis of aperture-shared arrays based on CDS is also discussed. Arrays own multiple subarrays can be obtained, so they can operate in a wide band.Finally, the synthesis of minimum redundancy arrays is introduced firstly. Then the application of Genetic Algorithm(GA) to the synthesis of thinned arrays is discussed. A method based on CDS and GA is presented, it can suppress the PSLL of arrays optimized by CDS further. A new wideband array concept that includes an aperture incorporating different sizes and inter-element spacings is introduced at last.