Extreme Beam Broadening using Phase Only Pattern Synthesis (original) (raw)
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General synthesis method for linear phased antenna array
IET Microwaves, Antennas & Propagation, 2008
An efficient phase-only control method is presented to synthesise directive lobe and multilobe patterns, and create adaptive nulls in interference direction. The proposed method is based on iterative minimisation of a function that incorporates constraints imposed in each direction with respect to excitation phases. To verify the performances of the proposed technique, an eight-element array has been realised and tested for various types of beam configurations.
Abstract – A rigorous deterministic approach is proposed for the mask-constrained power pattern synthesis of shaped beams through one-dimensional sparse arrays having uniform-amplitude excitations (and variable phases). The approach includes the well known density taper procedure as a special case. The corresponding technique, which exploits an analytical formulation of the problem and convex programming routines, results in fast computation and is able to achieve optimal solutions without recurring to any global optimization. Numerical results assessing the capabilities of the proposed design method are provided, opening the way to the development of an effective approach for the synthesis of circularly symmetric shaped beams via uniformly-excited circular ring arrays.
Pattern synthesis of linear phased arrays with optimized unit circle Boundary Conditions
2019
The present work perturbs the synthesis of linear array patterns in periodic phases in the presence of asymmetric element pattern and mutual coupling. To mitigate the above problems in small linear phased arrays, an approach proposed using a Schelkunoff’s unit circle z-plane coupled with PSO, with zeros in z-plane constrained using intelligently defined solution space boundary conditions. The proposed optimisation scheme achieves better radiation pattern objectives in addition of mutual coupling for scanned low side lobe beam sum pattern and wide band sector-beam pattern. Convergence performance comparisons have shown that the preferred scheme, IzBC-PSO, is faster, consistent and more accurate than other optimization techniques. Significant improvement in the results is obtained by using a Bow-tie dielectric resonator antenna in 4.5 to 5.5 GHz frequency ranges. Keywords-IZBC-PSO, Schelkunoff’s Unit Circle, Bowtie dielectric resonator antenna,Mutual Coupling, intelligently defined so...
An Effective Approach to the Synthesis of Phase Only Reconfigurable Linear Arrays
Abstract—We present an effective approach to the optimal mask-constrained power pattern synthesis of uniformly spaced array antennas able to dynamically reconfigure their radiation pattern by modifying only the excitation phases. The proposed approach results in a design procedure having a very low computational burden and, by exploiting at best the knowledge available in the separate synthesis of each pattern, is able to solve the underlying combinatorial optimization problem and to achieve solutions close (or equivalent) to the global optimum. A set of representative examples are reported in order to validate the proposed approach. Some extensions of the developed theory to cases other than linear arrays are also outlined.
The International Conference on Electrical Engineering
In this work, synthesis of linear array geometry is first formulated as a linearly constrained multi-objective optimization problem with the goals of minimum sidelobe level, null control and high directivity. Then solved by a Generalized Pattern Search (GPS) algorithm for the optimum element locations and excitation amplitudes. The constraints are imposed on the inter-element spacing and dynamic range ratio of the amplitude tapering to reduce mutual coupling effects between the elements. GPS methods are newly discovered, derivative-free methods where the current iterate is updated by sampling the fitness function at a finite number of points along a suitable set of search directions to find a decrease in the function value. Finally, two worked examples are presented that illustrate the use of GPS synthesis method, and the optimization goal in each example is easily achieved. Furthermore the full-wave simulations of the synthesized arrays are also completed to examine the mutual coupling effects. Finally the results of the GPS algorithm are validated by comparing with results obtained using the genetic algorithm, and the results of the uniform and Dolph-Chebyshev arrays, having the same number of element and the same aperture length.
Progress In Electromagnetics Research, 2012
In a large number of applications, including communications from satellites, an optimal exploitation of the available power is of the outmost importance. As a consequence, isophoric array architectures, i.e., arrays using the same power in all the different entry points and achieving the amplifiers' maximum efficiency, are of great interest. At the same time, the easy reconfigurability of the power patterns results fundamental in order to get a full exploitation of the payload. In this paper, an innovative and deterministic approach is proposed for the optimal synthesis of linear phase-only reconfigurable isophoric sparse arrays able to commute their pattern amongst an arbitrary number of radiation modalities. The introduced perspective leads to an effective solution procedure for the fast design of antennas with high performance, and does not recur to computationally expensive global-optimization techniques. Numerical results concerning applications of actual interest and employing realistic element patterns are provided in support of the given theory.
Phase-Only Nulling with Limited Number of Controllable Elements
Progress In Electromagnetics Research C, 2020
In this paper, the required array patterns with controlled nulls are obtained by optimizing only the excitation phases of a small number of elements on both sides of the array. A genetic algorithm is used to appropriately find which elements of the array to be optimized and also to find the required number of the excitation phases. The performance of the proposed phase-only method is compared with some other exciting methods, and it is found to be competitive, fulfil all the desired radiation characteristics, and represent a good solution for interference mitigation. Moreover, the proposed phaseonly array is designed and validated under realistic electromagnetic effects using CST full wave modeling. Experimental results are found in a good agreement with the theoretical ones and show realistic array patterns with accurate nulls.
Phase-Only Synthesis for Large Planar Arrays via Zernike Polynomials and Invasive Weed Optimization
IEEE Transactions on Antennas and Propagation, 2022
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Synthesis of Wide Beam Array Patterns Using Quadratic-Phase Excitations
Synthesis of wide-beam array antennas is investigated using phase-only technique. A quadratic phase distribution for the element excitations is proposed, while the magnitudes are kept uniform. The beam width and maximum level of the radiated field of the proposed array were compared with those obtainable from the conventional broadside array. Compared to the case of broadside array, the proposed method showed many fold increase in the -10dB beam width. Moreover, a reduction of up to 7.6dB for a 10-element array, and 13.6dB for the 40-element array have been obtained in the maximum level of the pattern. The proposed technique offers simple design method, and considerable reduction in the number of required phase shifters. The required number of phase shifters for an N-element array is (N/2-1), and (N-1)/2 for even, and odd number of elements N respectively.