Analysis and design of wideband antenna arrays

Çapraz, Kenan
Two methods of wideband array design are studied. The aim of this study is to investigate arrays with aperiodic spacings which are designed with these methods in order to obtain wideband behavior. These methods are genetic algorithm and wavelength scaled arrays that have active regions with variable interelement spacings. Genetic algorithm is utilized for array antennas with aperiodic spacing to optimize sidelobe levels of the antenna array in wide frequency band. Wavelength scaled spacing concept in designing arrays is benefited to design array with frequency independent radiation characteristics such as constant gain and beamwidth in the operational bandwidth. MATLAB® codes are developed in order to examine array factor of designed arrays with these methods. A feed network in order to implement active region concept is designed and realized. A fabricated linear Vivaldi antenna array with designed feed network is measured and its performance is compared with simulation results.


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Önol, Can; Ergül, Özgür Salih; Department of Electrical and Electronics Engineering (2015)
In this study, an optimization environment based on heuristic algorithms supported by the multilevel fast multipole algorithm (MLFMA) is presented for different antenna problems involving either excitation or geometry optimizations. The heuristic algorithms are implemented in-house by aiming more effective interactions between electromagnetic solvers and optimization algorithms, instead of black box interactions. Excitation optimizations of various array geometries for desired radiation characteristics are ...
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In practice, there exist many error sources which distort the antenna array pattern. For example, elements of antenna arrays influence each other (known as mutual coupling), mismatches in cables and element positions affects the antenna radiation pattern and also unequal gain and phase characteristics of RF receiver distorts the received signal. These effects generally degrade the array performance. They cause an increase in sidelobe levels with an accompanying decrease in gain. Also, these errors limit the...
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A new method is proposed that provides simple and effcient design and analysis algorithm for microstrip antennas with arbitrary patch shapes. The proposed procedure uses the mutiport network model (MNM) where the antenna is considered as a cavity bounded by perfect electric conductors on the top and the bottom surfaces and perfect magnetic conductor on the side surfaces. Ports are defined along the periphery of the patch, and the impedance matrix representing the voltage induced at one port due to a current...
Optimization of nonuniform array geometry for DOA estimation with the constraint on gross error probability
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In this work, a novel method is proposed to optimize the array geometry for DOA estimation. The method is based on minimization of fine error variances with the constraint that the gross error probability is below a certain threshold. For this purpose, a metric function that reflects the gross and fine error characteristics of the array is proposed. Theoretical analyses show that the minimization of this metric function leads to small DOA estimation error variance and small gross error probability. Analyses...
Citation Formats
K. Çapraz, “Analysis and design of wideband antenna arrays,” M.S. - Master of Science, Middle East Technical University, 2014.