Naslov
Synthesis of broadband microstrip antennas

Autori
Zentner, Radovan ; Šipuš, Zvonimir ; Bartolić, Juraj

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
Proceedings of the Millennium Conference on Antennas and Propagation, AP2000 / Danesy, D. ; Sawaya, H. - Noordwijk : European Space Agency, 2000, 0939/1-0939/4

Skup
Millennium Conference on Antennas and Propagation, AP2000

Mjesto i datum
Davos, Švicarska, 09.04.2000. - 14.04.2000

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
microstrip antennas; method of moments; optimization methods

Sažetak
The paper describes synthesis procedure of broadband stacked rectangular patches. Stacked patches for linearly polarised broadband applications became a common design in last years. If excited at the symmetry axis of a driven patch, linearly polarized, high-gain antenna with over 20% of bandwidth can be achieved. In order to apply this approach for circular polarization, the probe must be displaced off the symmetry axis. The driven and parasitic rectangular patches are of different dimensions of optimal values, places centered one above the other. The development of such designs needs some numerical optimisation to be performed, since there is no accurate analytical model for these structures. The numerical optimisation is very CPU time consuming, since the rigorous computation of the antennas (MoM) must be called thousands of times during the procedure. An optimisation of a stacked patch configuration has up to ten unknowns, which represents a hard multidimensional optimisation problem with a lot of local minima. If optimised using some direct search method, e. g. quasi-Newton method, fast convergence can be achieved. However, due to convergence to local minima, the final antenna performance would strongly depend on the initial guess for the optimisation. Therefore, the genetic algorithm, a global optimisation tool, is applied for obtaining a good initial guess for some direct search method. Here, the Steady-state genetic algorithm was used for primary search of the whole cost function domain and arriving near the best solution, and the quasi-Newton method was applied for the fast convergence to it. The antenna was modeled using simple method of moments and Galerkin procedure in spectral domain with entire domain basis functions. This gave an accurate and still relatively fast cost function. The antennas are designed for 2 GHz band, and its performance calculated at five frequencies in approximately 10% of bandwidth. Respecting both, impedance matching and axial ratio in whole band of interest results in a cost-benefit design. Some experimental results confirmed the procedure.

Izvorni jezik
Engleski

Znanstvena područja
Elektrotehnika

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