Pattern Synthesis Of Conformal Arrays Research Articles

ANN-Assisted Iterative Algorithms for Pattern Synthesis of Conformal Arrays

ANN-Assisted Iterative Algorithms for Pattern Synthesis of Conformal Arrays

Synthesis of Elliptically Shaped Aperiodic Antenna Arrays Subject to Complex Design Constraints

AbstractState‐of‐the‐art conformal array pattern synthesis techniques typically suffer from a significant computational burden. This article builds upon the auxiliary array pattern synthesis technique, allowing the technique to work on elliptical contours. This deterministic method is both computationally efficient and capable of handling complex design cases with additional design constraints. In order to highlight the versatility and applicability, the method has been applied to an elliptical arc array comprised of Rampart antennas and an elliptical ring array using dipole elements. The results have been validated through full‐wave electromagnetic simulations, as well as physical measurements. Both arrays presented show good agreement with the proposed synthesis technique. Highlighting the ability to satisfy additional design constraints, such as enforcing a minimal element spacing or having a controlled beamformer‐network complexity.

Simple Matrix Equation (SME) Method for Pattern Synthesis of Conformal Antenna Array with Arbitrary Architecture

A novel noniterative method for pattern synthesis of conformal antenna array is put forward. First, a new pattern function formula for general conformal antenna array is derived. Then, according to the new pattern function formula, a new block matrix equation (BME) and a simple matrix equation (SME) are obtained. SME has the same form as the equation of linear array pattern synthesis. The new method can be applied to pattern synthesis of any conformal array. Moreover, due to SME having the same form as the matrix equation of linear array pattern synthesis, the new simple matrix equation can be dealt with by the approaches for linear array pattern synthesis, which significantly expands the existing approaches for conformal antenna array pattern synthesis. Two different conformal array configurations are taken as the examples to demonstrate the advantages of the new method. Results of the simulations show that the new method can flexibly and effectively be applied to synthesize patterns for various conformal array architectures.

Study on pattern synthesis of conformal array using enhanced adaptive genetic algorithm

ABSTRACTInvestigations on an enhanced adaptive genetic algorithm (EAGA) for pattern synthesis of a conformal array are presented. The proposed algorithm uses the advantages of the adaptive genetic algorithm (AGA) and the invasive weed optimization so that it improves the searching ability and the convergence speed. Convergence characteristics of the EAGA are compared with those of the AGA. Also, the pattern synthesis performance of the EAGA is compared with that of the AGA. A 4 × 16 conformal array operating as a 1 × 16 array in the azimuth direction is fabricated and measured to demonstrate the proposed algorithm. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1173–1176, 2015

Conformal Array Pattern Synthesis and Activated Elements Selection Strategy Based on PSOGSA Algorithm

The pattern synthesis and activated element selection for conformal array is investigated based on hybrid particle swarm optimization-gravitational search algorithm (PSOGSA) in this paper. With the introduction of PSOGSA algorithm which is a novel hybrid optimization technique, the element excitations are optimized to obtain the desired pattern for conformal array in the case of considering uncoupled and coupled element pattern. Numerical simulation and full-wave electromagnetic calculation verify the advantage and efficiency of our method. Then, a novel strategy of activated element selection based on PSOGSA algorithm is proposed for saving the energy consumption in conformal array.

A Hybrid IWO/PSO Algorithm for Pattern Synthesis of Conformal Phased Arrays

This communication introduces a hybrid invasive weed optimization and particle swarm optimization (IWO/PSO) algorithm dedicated to pattern synthesis of conformal arrays. A 3 $\, \times \,$ 9 cylindrical conformal microstrip array is studied to demonstrate the proposed algorithm. The active element pattern of each element in the conformal array is extracted and the phase and amplitude of each excited voltage are optimized to achieve the required goals using the hybrid IWO/PSO algorithm. The results indicate that, compared with standard IWO and PSO algorithms, the introduced hybrid algorithm maintains the respective advantages of the IWO and PSO algorithms while excluding their respective deficiencies. Moreover, the hybrid algorithm is very reliable in achieving global optimality.

Hybrid alternate projection algorithm and its application for practical conformal array pattern synthesis

Based on the fabricated 12-element cavity-backed microstrip sector cylinder array, a novel hybrid alternate projection algorithm (HAPA), which combines analytical method with numerical techniques effectively, is proposed for synthesizing the pattern of practical conformal array. The algorithm applies the variable direction aperture projection method with mutual coupling correction techniques to provide the good initial excitations of elements to the enhanced alternate projection algorithm (EAPA). In order to do further optimization, which improves the convergent speed of the algorithm significantly. Finally, the HAPA has been applied to the fabricated sector cylinder array with mutual coupling considered. The results of synthesized patterns, such as low sidelobe with null points formed pattern, beam scanning with low sidelobe pattern and the shaped beam pattern are presented. It demonstrates the validity of HAPA in practical conformal array synthesis.

Conformal array pattern synthesis using the weighted alternating reverse projection method considering mutual coupling and embedded-element pattern effects

This article generalises a pattern synthesis technique to conformal arrays. An iterative method is used for optimisation of element excitations in an array of rectangular patch elements that are conformed to a hemispheric surface. The embedded-element co-polarisation and cross-polarisation patterns are evaluated using a full-wave method. These patterns are used in a newly introduced iterative synthesis algorithm to obtain the minimum sidelobe level (SLL) and cross-polarisation level (XPL). The mutual coupling effects on the synthesis results are investigated in this procedure. The synthesised patterns show adequate XPL and SLL comprised to other methods. The weighted alternating reverse projection (WARP) method is modified and it is shown that the WARP method can synthesise lower XPL and SLL than those of other methods. Compared with other synthesis method, the WARP improves SLL by 2 dB and XPL by about 1.5 dB in 19 element array.

A Hybrid Optimization Algorithm and Its Application for Conformal Array Pattern Synthesis

Investigations on conformal phased array pattern synthesis using a novel hybrid evolutionary algorithm are presented. First, in order to overcome the drawbacks of the standard genetic algorithm (GA) and the particle swarm optimization (PSO), an improved genetic algorithm (IGA) and an improved particle swarm optimization (IPSO) algorithm are proposed by introducing novel mechanisms. Then, inspired by the idea of grafting in botany, a hybrid algorithm called HIGAPSO is proposed, which combines IGA and IPSO to take advantages of both methods. After that, a spherical array antenna using wide-band stacked patch antenna elements is selected as a synthesis example to illustrate the power of HIGAPSO in solving realistic optimization problems. Finally, HIGAPSO is used to optimize the amplitude of the element current excitation of the spherical conformal array. Experimental results show that the hybrid algorithm is superior to GAs and PSOs when applied to both the classical test function and the practical problem of conformal antenna array synthesis.

Frequency-invariant pattern synthesis of conformal array antenna with low cross-polarisation

Despite their potential and promising advantages over classical planar arrays, conformal arrays also present many challenges to the antenna designer, including varying element normal due to curvature, serious cross-polarisation effect, limited operational bandwidth and so on. A uniform method for the element polarised pattern transformation of arbitrary 3D conformal arrays is presented based on Euler rotation. A space–time-polarisation filter structure is proposed for the pattern synthesis of conformal array, in which the finite impulse response (FIR) filters assigned to every element are used to acquire the frequency-invariant array pattern and the element polarisation diversity in array global coordinates is used to depress the cross-polarisation level. The optimal weight vector is obtained by alternating projection method. The alternating projection method is a powerful and attractive method for the pattern synthesis in that it requires relatively smaller amount of computation burden and a wide variety of desirable constraints can be freely implemented in a ‘visible’ way, which is usually impossible for other optimisation method. The pattern synthesis method proposed has established a unified frame for the frequency-invariant and low cross-polarisation pattern synthesis of conformal array. Simulation results are provided to demonstrate the effectiveness and behaviour of the proposed method.

Pattern synthesis of conformal arrays by the simulatedannealing technique

A design method previously developed for the synthesis of antenna patterns of circular arc arrays is shown to also be applicable to the synthesis of conformal arrays in the 3D case. This method uses the flexibility of the simulated annealing technique to achieve the excitations of the elements for a desired radiation pattern. The algorithm allows the inclusion of constraints in the variability of the excitations in the synthesis procedure, as well the control of the sidelobe level, the beamwidth and any desired design specification.

A new low-side-lobe pattern synthesis technique for conformal arrays

The application of the new nonlinear optimization algorithms to array design is demonstrated by the low-side-lobe pattern synthesis of conformal arrays. By adopting the information of array element realized gain patterns the authors formulate synthesis problems as nonlinearly constrained optimization problems, and propose a direct method to solve them. The technique allows them to find a set of array coefficients that yield a pattern meeting a specified side-lobe level and achieving the maximum directivity, if such a set of array coefficients exists. If the side-lobe specifications cannot be met with the given array, the technique will result in a set of coefficients that yield a pattern meeting the best attainable side-lobe level and having directivity as high as possible. Simplified synthesis problems for an axial dipole array in an infinite, perfectly conducting cylinder are discussed, and numerical results are given. The synthesis technique works for general array patterns. >