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Wyszukujesz frazę "Koziel, Slawomir" wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Inverse and forward surrogate models for expedited design optimization of unequal-power-split patch couplers
Autorzy:
Koziel, Slawomir
Bekasiewicz, Adrian
Powiązania:
https://bibliotekanauki.pl/articles/220645.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
inverse modelling
patch coupler
computer-aided design
forward modelling
unequal-split coupler
Opis:
In the paper, a procedure for precise and expedited design optimization of unequal power split patch couplers is proposed. Our methodology aims at identifying the coupler dimensions that correspond to the circuit operating at the requested frequency and featuring a required power split. At the same time, the design process is supposed to be computationally efficient. The proposed methodology involves two types of auxiliary models (surrogates): an inverse one, constructed from a set of reference designs optimized for particular power split values, and a forward one which represents the circuit S-parameter gradients as a function of the power split ratio. The inverse model directly yields the values of geometry parameters of the coupler for any required power split, whereas the forward model is used for a post-scaling correction of the circuit characteristics. For the sake of illustration, a 10-GHz circular sector patch coupler is considered. The power split ratio of the structure is re-designed within a wide range of -6 dB to 0 dB. As demonstrated, precise scaling (with the power split error smaller than 0.02 dB and the operating frequency error not exceeding 0.05 GHz) can be achieved at the cost of less than three full-wave EM simulations of the coupler. Numerical results are validated experimentally.
Źródło:
Metrology and Measurement Systems; 2019, 26, 3; 463-473
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A design framework for rigorous constrained EM-driven optimization of miniaturized antennas with circular polarization
Autorzy:
Bekasiewicz, Adrian
Koziel, Slawomir
Powiązania:
https://bibliotekanauki.pl/articles/220503.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
axial ratio
antenna miniaturization
circular polarization antenna
constrained optimization
EM-driven design
Opis:
Compact radiators with circular polarization are important components of modern mobile communication systems. Their design is a challenging process which requires maintaining simultaneous control over several performance figures but also the structure size. In this work, a novel design framework for multi-stage constrained miniaturization of antennas with circular polarization is presented. The method involves sequential optimization of the radiator in respect of selected performance figures and, eventually, the size. Optimizations are performed with iteratively increased number of design constraints. Numerical efficiency of the method is ensured using a fast local-search algorithm embedded in a trust-region framework. The proposed design framework is demonstrated using a compact planar radiator with circular polarization. The optimized antenna is characterized by a small size of 271 mm2 with 37% and 47% bandwidths in respect of 10 dB return loss and 3 dB axial ratio, respectively. The structure is benchmarked against the state-of-the-art circular polarization antennas. Numerical results are confirmed by measurements of the fabricated antenna prototype.
Źródło:
Metrology and Measurement Systems; 2019, 26, 1; 41-52
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reduced-cost design closure of antennas by means of gradient search with restricted sensitivity update
Autorzy:
Kozieł, Sławomir
Pietrenko-Dąbrowska, Anna
Powiązania:
https://bibliotekanauki.pl/articles/221401.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
antenna design
design closure
EM-driven optimization
gradient search
sensitivity update
Opis:
Design closure, i.e., adjustment of geometry parameters to boost the performance, is a challenging stage of antenna design process. Given complexity of contemporary structures, reliable parameter tuning requires numerical optimization and can be executed using local algorithms. Yet, EM-driven optimization is a computationally expensive endeavour and reducing its cost is highly desirable. In this paper, a modification of the trust-region gradient search algorithm is proposed for accelerated optimization of antenna structures. The algorithm is based on sparse updates of antenna sensitivities involving various methods that include the Broyden formula used for selected parameters, as well as dimensionality- and convergence-dependent acceptance thresholds which enable additional speedup, and make the procedure easy to tune for various numbers of antenna parameters. Comprehensive verification executed for a set of benchmark antennas delivers consistent results and considerable cost reduction of up to 60 percent with respect to the reference algorithm. Experimental validation is also provided.
Źródło:
Metrology and Measurement Systems; 2019, 26, 4; 595-605
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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