Pattern synthesis and broad nulling optimization of STMLAA with EM simulation

• Published in: International journal of numerical modelling Vol. 31; no. 5
• Main Authors: Ram, Gopi, Panduro, Marco A., Reyna, Alberto, Kar, Rajib, Mandal, Durbadal
• Format: Journal Article
• Language: English
• Published: Bognor Regis Wiley Subscription Services, Inc 01.09.2018
• Subjects: Algorithms; Angle of arrival; antenna array; Antenna arrays; Antenna radiation patterns; Computer simulation; electromagnetic modelling (EM); Evolutionary algorithms; Genetic algorithms; Heuristic methods; memetic FPA; Microstrip antennas; microstrip patch antenna; Particle swarm optimization; Patch antennas; side lobe level; Sidelobe reduction; Sidelobes; Simplex method; Statistical analysis; Synthesis; time modulation
• ISSN: 0894-3370; 1099-1204
• DOI: 10.1002/jnm.2322

An accurate imposing of broad nulls in the side lobe levels of radiation pattern of the symmetric time modulated linear antenna array (STMLAA) is proposed in this article. The broad nulls are intended to be imposed in the range of the angular sector of 40° to 70° of angle of arrival in θ plane which is symmetrical to the main beam of the radiation pattern. The metaheuristic evolutionary algorithm with the hybridization of flower pollination algorithm with Nelder‐Mead simplex method called memetic flower pollination algorithm is used uniquely for the application of pattern synthesis to serve this purpose. The optimized results obtained by using memetic flower pollination algorithm are validated by using Computer Simulation Technology Microwave Studio by taking practical elements of microstrip patch antenna. From algorithm's point of view, the superiority of the adopted algorithm has been justified by the statistical analysis performed along with the basic algorithms, like real‐coded genetic algorithm, particle swarm optimization, and differential evolution. 16‐, 32‐, and 64‐element STMLAA are realized to demonstrate the proposed concept. Broad nulls are aimed to be obtained by the optimal perturbations of switching time sequences and the interelement separations of the elements having symmetricity with respect to the main beam of the radiation pattern. Moreover, the maximum side lobe level is also reduced as compared with that of the uniform linear antenna array for the same element. The microstrip patch antenna with operating frequency of 5.85 GHz has been designed, which is applicable for Wi‐Max application. The concept of pattern multiplication is applied to multiply the element pattern of patch antenna and the array factor of STMLAA of isotropic elements.