Design of circular arrays (CAs) and hexagonalarrays (HAs) with low sidelobe level (SLL) and high directivity is usually achieved by increasing the number of array elements, which leads to a high undesired mutual coup...
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Design of circular arrays (CAs) and hexagonalarrays (HAs) with low sidelobe level (SLL) and high directivity is usually achieved by increasing the number of array elements, which leads to a high undesired mutual coupling. Therefore this study presents an efficient optimisation method and a framework to show how to design multi-ring concentric CAs (CCA) and concentric HAs (CHAs) configurations using a hybrid enhanced particle swarm optimisation and differential evolution (hybrid EPSO/DE) optimisation technique. The presented optimum CCA and CHA have perfect invariant SLL and high directivity with low mutual coupling by keeping the inter-element spacing not less than half a wavelength which is not possible to be achieved in CA and HA arrangements. Different configurations with two-rings, three-rings and four-rings are presented. The rotation angle of outer rings and the complex excitations of array elements are first optimised. Then, this design is further optimised using a time modulation technique by controlling the switch-on times and the phases of elements excitations of the best CCA and CHA array designs. The presented time modulated (TM) concentric CA and TM concentric HA designs attain ultra-low SLL, reduced sideband level and maximised directivity besides reducing the dynamic range of the array excitations.
Side lobes and interference signals result in decreased performance of antennaarray. In this paper a method to reduce the side lobe levels (SLL) and for rejecting the interference signals in concentrichexagonal Ante...
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ISBN:
(纸本)9781665452038
Side lobes and interference signals result in decreased performance of antennaarray. In this paper a method to reduce the side lobe levels (SLL) and for rejecting the interference signals in concentric hexagonal antenna array (CHAA) using differential evolutionary (DE) algorithm is presented. CHAA will give lower SLL compared to circular and linear antennaarrays and are hence preferred in the presented method. DE algorithm is an evolutionary algorithm in which mutations are performed by combination of individuals and an optimized solution is obtained. The simulation results are presented for a single ring CHAA, 4 ring CHAA with 2 different interference signal scenarios and a 6 ring CHAA with 2 different interference signal scenarios. From the results it can be inferred that there is a 6 dB SLL reduction in single ring CHAA and at least 8 dB and 9 dB SLL reduction in 4 and 6 ring CHAA. Also, nulls with a minimum of -60dB have been placed in 4 different interference signal scenarios.
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