Searcharxiv⌕ Search

arXiv subjects

Khadijeh Askaripour

Publications and source records attributed to Khadijeh Askaripour.

3 recordsLinked to original sources

A Bi-Stage Framework for Automatic Development of Pixel-Based Planar Antenna Structures

Development of modern antennas is a cognitive process that intertwines experience-driven determination of topology and tuning of its parameters to fulfill the performance specifications. Alternatively, the task can be formulated as an optimization problem so as to reduce reliance of geometry selection on engineering insight. In this work, a bi-stage framework for automatic generation of antennas is considered. The method determines free-form topology through optimization of interconnections between components (so-called pixels) that constitute the radiator. Here, the process involves global optimization of connections between pixels followed by fine-tuning of the resulting topology using a surrogate-assisted local-search algorithm to fulfill the design re-quirements. The approach has been demonstrated based on two case studies concerning development of broadband and dual-band monopole antennas.

math.NA↗

Unsupervised Surrogate-Assisted Synthesis of Free-Form Planar Antenna Topologies for IoT Applications

Design of antenna structures for Internet of Things (IoT) applications is a challenging problem. Contemporary radiators are often subject to a number of electric and/or radiation-related requirements, but also constraints imposed by specifics of IoT systems and/or intended operational environments. Conventional approaches to antenna design typically involve manual development of topology intertwined with its tuning. Although proved useful, the approach is prone to errors and engineering bias. Alternatively, geometries can be generated and optimized without supervision of the designer. The process can be controlled by suitable algorithms to determine and then adjust the antenna geometry according to the specifications. Unfortunately, automatic design of IoT radiators is associated with challenges such as determination of desirable geometries or high optimization cost. In this work, a variable-fidelity framework for performance-oriented development of free-form antennas represented using the generic simulation models is proposed. The method employs a surrogate-assisted classifier capable of identifying a suitable radiator topology from a set of automatically generated (and stored for potential re-use) candidate designs. The obtained geometry is then subject to a bi-stage tuning performed using a gradient-based optimization engine. The presented framework is demonstrated based on six numerical experiments concerning unsupervised development of bandwidth-enhanced patch antennas dedicated to work within 5 GHz to 6 GHz and 6 GHz to 7 GHz bands, respectively. Extensive benchmarks of the method, as well as the generated topologies are also performed.

math.NA↗

Strategies for Feature-Assisted Development of Topology Agnostic Planar Antennas Using Variable-Fidelity Models

Design of antennas for contemporary applications presents a complex challenge that integrates cognitive-driven topology development with the meticulous adjustment of parameters through rigorous numerical optimization. Nevertheless, the process can be streamlined by emphasizing the automatic determination of structure geometry, potentially reducing the reliance on traditional methods that heavily rely on engineering insight in the course of antenna development. In this work, which is an extension of our conference paper [1], a specification-oriented design of topologically agnostic antennas is considered by utilizing two strategies focused on bandwidth-specific design and bandwidth-enhanced optimization. The process is embedded within a variable-fidelity framework, where the low-fidelity optimization involves classification of randomly generated topologies, followed by their local tuning using a trust-region algorithm applied to a feature-based representation of structure response. The final result is then tuned using just a handful of high-fidelity simulations. The strategies under consideration were verified on a case study basis concerning automatic generation of three radiators with varying parameters. Benchmarks of the algorithm against more standard optimization methods, as well as comparisons of the obtained topologies with respect to state-of-the-art antennas from literature have also been considered.

math.NA↗