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This work addresses directivity improvement of a fan-beam antenna using local constrained optimization. More specifically, it demonstrates that adjustment of elementary patch sizes of a gridded patch antenna considerably improves antenna directivity without increasing its footprint. This indicates that utilization of all available degrees of freedom, i.e., genetic algorithm (GA) optimization and continuous...
A systematic procedure for design of a broadband circularly polarized dielectric resonator antenna (CP DRA) is presented. An important stage of this process is the design of a microstrip branchline coupler that realizes a required excitation of a particular dual-input CP DRA over the frequency range of interest. This excitation is developed to improve the axial ratio, otherwise degraded due to coupling...
A systematic approach to sidelobe reduction of broadside linear antenna arrays using corporate feeds implementing non-uniform excitation is proposed. Only the corporate feeds that consist of equal-power split T-junctions, i.e., the simplest power dividers, are considered. First, for a given particular array aperture, candidate feeds (excitation sets) are searched among excitation sets which might...
Simulation-based optimization is demonstrated for design of broadside linear microstrip antenna arrays energized through corporate feeds. Corporate feeds that are of interest here implement non-uniform amplitude excitation while include only equal-power split T-junctions as power distributing elements. A corporate feed designed and simulated as stand-alone microstrip circuit provides required complex...
A novel procedure for automated simulation-driven tuning of circularly polarized (CP) microstrip patch antennas (MPA) for improved axial ratio (AR) is presented. Our approach specifically addresses the CP MPAs exited through dual inputs which are driven by branch line couplers of unequal power splits. Our procedure allows for the improvement of AR over the required range of operating frequencies....
A computationally efficient procedure for automated electromagnetic (EM) simulation-driven design tuning of circularly polarized microstrip patch antennas has been presented. Our approach allows for design improvement of all important figures of merit of the antenna at hand over the frequency, including axial ratio, realized gain, and reflection coefficient. Simultaneous adjustment of all relevant...
A novel approach to improve axial ratio (AR) and axial ratio bandwidth (ARB) of circular polarized (CP) dielectric resonator antennas (DRA) excited with dual-point feeds is presented. It is applicable to different CP DRA cross sections excited though two inputs with a 90-degree angular separation. First, excitation of the DRA ports that substantially improves AR in the broadside direction at the CP...
In the paper, a novel topology of a miniaturized wideband dual-band rat-race coupler has been presented. Small size of the circuit has been obtained by meandering transmission lines of the conventional circuit. At the same time, the number of independent geometry parameters has been increased in order to secure sufficient circuit flexibility in the context of its design optimization for dual-band...
In this paper, a technique for low-cost statistical analysis and yield estimation of compact microwave couplers has been presented. The analysis is executed at the level of a fast surrogate model representing selected characteristic points of the coupler response that are critical to determine satisfaction/violation of the prescribed design specifications. Because of less nonlinear dependence of the...
A technique for rapid simulation-based design of planar antenna arrays is presented. The proposed approach is based on establishing a suitable correction of the analytical array factor model of the array of interest. The corrected array factor is utilized as a fast surrogate allowing us to find the optimum element spacing and phase excitations at low computational cost. The correction terms are iteratively...
In this paper, computationally efficient design optimization of a miniaturized dual-band microstrip branch-line coupler is presented. Our optimization approach relies on suitably extracted features of a highly nonlinear response of the coupler structure under design. By formulating the design objectives in terms of the feature point locations, we carry out iterative optimization of the linear model...
We consider simulation-based sidelobe suppression, for pencil-beam planar arrays comprising individually fed microstrip antennas, realized by phase-only and position-only adjustment. The adjustment is carried out through numerical optimization of a discrete electromagnetic (EM) simulation as a high-fidelity model with the aid of a properly corrected fast array factor. Enhancement of sidelobe suppression...
A methodology for expedited simulation-based design of microstrip linear antenna arrays is presented. Our approach utilizes response-corrected array factor model as well as surrogate-based optimization of the array elements for simultaneous control of both the radiation and reflection responses of the array. The technique is demonstrated using a 16-element array of slot-fed microstrip patch antennas.
In the paper, antenna array optimization by means of an enhanced surrogate model-aware evolutionary search (SMAS) framework is presented. The enhancements aim at improving local optimization capabilities of SMAS. The local search engine, exploiting a surrogate assisted trust-region-based local search algorithm ORBIT is launched to fine-tune the solutions generated by SMAS to further decrease the optimization...
Feasible EM-driven design of microstrip antenna subarrays through surrogate-based optimization (SBO) is proposed. By exploiting SBO and variable-fidelity EM simulations, our approach allows simultaneous and low-cost optimization of both array and feed parameters for low side lobs and low reflection.
A methodology for computationally efficient simulation-driven design of microstrip antenna subarrays is presented. Our approach takes into account the effect of the feed (e.g., a corporate network) on the subarray side lobe level and allows adjusting both radiation and reflection responses of the structure under design within a single automated process. This process is realized as surrogate-based...
Surrogate-based optimization (SBO) is applied to design of planar antenna arrays. Design goals include radiation pattern optimization and matching at the element terminals. Our approach uses two low-fidelity models: an array model based on the single element radiation response combined with the analytical array factor, and a discrete coarse-mesh electromagnetic (EM) model of the entire array. Both...
The performance of the space mapping (SM) optimization algorithm depends both on approximation and generalization capabilities of the underlying surrogate model. Often, the surrogate is selected by trial and error which may lead to excessive computational overhead and poor quality of the optimization outcome. Here, we introduce an adaptively constrained parameter extraction process to automatically...
Computationally efficient design optimization methodology for ultra-wideband (UWB) antennas is proposed. Our technique exploits space mapping with the underlying surrogate model built using kriging interpolation of the coarse-discretization EM simulation data. Robustness of the proposed approach is demonstrated through the design of two UWB planar antennas. In both cases, an optimized design is obtained...
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