This study presents the study of beamforming capabilities of arrays installed on a non‐conductive unmanned aerial vehicle (UAV). The main purposes of this study are the application of a beamforming algorithm by including the airframe in the optimisations and the study of simplifications of the aircraft model, so as to allow performing full‐wave simulations, even though the UAV is much larger than the operating wavelength. To validate the simplified electromagnetic model, antenna arrays have been designed and installed onto the UAV. Radiation pattern measurements demonstrate that the proposed simplifications yielded very good radiation pattern predictions and can be used as guidelines for simulation of other kinds of non‐conductive aircrafts.
This paper presents the application of optimization methods for the synthesis of a linear array to operate in the frequency range of 4G technology in Brazil. The desired pattern shall exhibit squared-cosecant shape, so as to provide uniform distribution of power inside the base station cell and to reduce co channel interference. Such an array is well suited to operate as a radio base station of mobile communications systems. The synthesis is performed by a combination of optimization methods: the genetic algorithm, which is used for the initial global search, and the sequential quadratic programming, which is applied for local refinement of the solution. This approach allows faster convergence than using only one kind of optimization method. The technique is demonstrated for a linear array of isotropic elements and, subsequently, for an array of E shaped microstrip antennas.
This paper presents an analysis for optimal design of switched beamforming applied to a linear array for wireless communication systems. The beam switching scheme provides coverage of a given sector in azimuth and controls the sidelobe level simultaneously. The analysis was developed considering arrays composed of Quasi-Yagi elements. The model assumes a user moving in the azimuthal direction under a constant velocity and with an estimation of the signal-to-noise ratio (SNR) at the mobile user (MU). The radio base station applies the beam that yields the best performance during transmission. The decision is based on the feedback information received from the MU. The goal of the analysis is to determine the best trade-off between the array size and number of feedback bits necessary to maximize the SNR at the receiver. The results show that a compromise between the number of beam-pointing directions and the array size should be taken into consideration for a wireless communication system design.
This study presents a technique to design antenna arrays with shaped radiation pattern. The efficiency of the proposed technique is demonstrated for the optimisation of a linear microstrip array for radio base stations of mobile communication systems. The main beam is shaped so as to provide uniform distribution of power inside a sector of a cell and to minimise the power radiated above the horizon. The synthesis of the shaped pattern is achieved by a combination of genetic algorithm and sequential quadratic programming. In contrast to several papers found in the literature that consider only isotropic antennas, the proposed approach takes into account all the radiation properties of small arrays, such as the mutual coupling between the array elements and edge effects. Finally, the design of the feeding system to produce the synthesised pattern is discussed. Measurements are used to validate the proposed technique.
This paper presents a four-element linear array composed of E-shaped microstrip antennas designed to switchedbeam application in ISM (Industrial, Scientific and Medical) radio band. Particle Swarm Optimization (PSO) algorithm is used to optimize four different sets of amplitude and progressive phase shift to achieve four distinct radiation patterns controlling the major lobe direction and sidelobe level. For this application, two restrictive approaches are presented for the implementation of PSO in order to guide the algorithm to feasible solutions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.