Abstract-In order to overcome drawbacks of standard particle swarm optimization (PSO) algorithm, such as prematurity and easily trapping in local optimum, a modified PSO algorithm which adopts a global best perturbation, is used to optimize the pattern of cylindrical conformal antenna array for sidelobe level (SLL) suppression and null control in certain directions. The convergence speed and accuracy of the algorithm are improved. Compared with genetic algorithm and simulated annealing, The PSO algorithm is much easier to understand and implement. Firstlypattern formula of conformal array is provided, then, the standard and modified PSO algorithm are introduced, at last, application examples and simulation results are presented. The results show that the Modified PSO algorithm is an effective and efficient method to solve multi-dimension and nonlinear problem.

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A practical capacitive circuit absorber with low ohm resistive sheets is presented, which is constructed by multilayer low ohm resistive sheets, polymethacrylimide foam and polyethylene terephthalate. For convenience of manufacture and practical engineering applications, a unique low ohm rectangular resistive sheet with a rotational symmetry pattern is employed, which is used to replace high ohm square resistive sheets. Based on the design of the low ohm sheet pattern and the absorber configuration, a prototype absorber is fabricated. The measured results show that the reflectivity of the absorber with a total thickness of 17.9 mm is −10 dB in 1.5-18 GHz for normal incidence. The absorber is shown to have the characteristics of low density and high intensity.

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