Adrian Bekasiewicz

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In this paper, the problem of geometry scaling of compact microwave structures is investigated. As opposed to conventional structures [i.e., constructed using uniform transmission lines (TLs)], re-design of miniaturized circuits (e.g., implemented with artificial TLs) for different operating frequencies is far from being straightforward due to considerable(More)
In this paper, a novel structure of a miniaturized microstrip rat-race coupler has been proposed. Surrogate-based optimization procedures are applied to explicitly reduce the coupler size while maintaining equal power split at the operating frequency of 1 GHz and sufficient bandwidth for return loss and isolation characteristics. The optimization is(More)
In this paper, a methodology for fast multiobjective optimization of the miniaturized microwave passives has been presented. Our approach is applicable to circuits that can be decomposed into individual cells [e.g., compact microstrip resonant cells (CMRCs)]. The structures are individually modeled using their corresponding equivalent circuits and aligned(More)
In this paper, a novel structure of a compact UWB slot antenna has been presented. For improved flexibility of the design, the slot is parameterized using splines. All antenna dimensions are simultaneously adjusted using numerical optimization procedures, which leads to a very compact footprint of 199 mm<sup>2</sup> and acceptable matching within the entire(More)
In this paper, a novel methodology for cost-efficient microwave design optimization in the frequency domain is proposed. Our technique, referred to as adaptive response scaling (ARS), has been developed for constructing a fast replacement model (surrogate) of the high-fidelity electromagnetic-simulated model of the microwave structure under design using its(More)
Re-designing circuits for various sets of performance specifications is an important problem in microwave and antenna engineering. Unfortunately, this is a difficult task that is normally realized as a separate design process, which is often as expensive (in computational terms) as obtaining the original design. In this work, we consider the application of(More)
The paper presents a technique for fast design optimization of compact microwave structures using multi-fidelity electromagnetic (EM) simulations. In our approach, sequential optimization of EM models of increasing fidelity is supplemented by a design refinement step exploiting fast response surface approximation model and space mapping. The technique is(More)
Multi-objective optimization of antenna structures in highly-dimensional parameter spaces is investigated. For expedited design, variable-fidelity EM simulations and domain patching algorithm are utilized. The results obtained for a monopole antenna with 13 geometry parameters are compared with surrogate-assisted optimization involving response surface(More)