ICTACT Journal on Communication Technology

R. Muralidaran ¹, A. Vallavaraj ¹, Hemant Patidar ², G. K. Mahanti ²

Affiliations
1 Department of Electronic and Computer Engineering, Caledonian College of Engineering, OM
2 Department of Electronics and Communication Engineering, National Institute of Technology, Durgapur, IN

Abstract

The influence of evolutionary algorithms enhanced its scope of getting its existence in almost every complex optimization problems. In this paper, cuckoo search algorithm, an algorithm based on the brood parasite behavior along with Levy weights has been proposed for the radiation pattern correction of a linear array of isotropic antennas with uniform spacing when failed with more than one antenna element. Even though deterioration produced by the failure of antenna elements results in various undesirable effects, consideration in this paper is given to the correction of side lobe level and null placement at two places. Various articles in the past have already shown that the idea to correct the radiation pattern is to alter the amplitude weights of the remaining unfailed elements, instead of replacing the faulty elements. This approach is made use of modifying the current excitations of unfailed elements using cuckoo search algorithm such that the resulting radiation pattern is similar to the unfailed original pattern in terms of side lobe level and null placement at two places. Examples shown in this paper demonstrate the effectiveness of this algorithm in achieving the desired objectives.

Keywords

Array Failure Correction, Linear Array, Cuckoo Search Algorithm, Side Lobe Level, Multiple Null Placement.

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R. Muralidaran ¹, A. Vallavaraj ¹, Hemant Patidar ², G. K. Mahanti ²

Affiliations
1 Department of Electrical and Computer Engineering, Caledonian College of Engineering, OM
2 Department of Electronics and Communication Engineering, National Institute of Technology, Durgapur, IN

Abstract

In this paper, the authors have proposed a method based on Quantum Particle Swarm Optimization (QPSO) algorithm in the context of radiation pattern correction of a linear array of isotropic antennas corrupted with one or more faulty antenna elements. Care is taken to maintain the values of side lobe level and maximum Wide Null Placement of the corrected pattern to be identical to the values of nondefective radiation pattern. This correction is made possible by altering the beam weights of the remaining elements in the array. The advantage of this method is that the necessity of replacement of the faulty elements is eliminated. Simulation is done on the linear antenna array constructed of individual isotropic elements separated by identical inter-element spacing and the results obtained from the simulation depict the effectiveness of the proposed method. This method can also be extended to other array geometries.

Keywords

Antenna Array, Failure Correction, Quantum Particle Swarm Optimization, Side Lobe Level, Wide Null Placement.

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A. Chatterjee ¹, G. K. Mahanti ¹

Affiliations
1 Department of Electronics and Communication Engineering, National Institute of Technology, Durgapur, IN

Abstract

Reduction of sidelobe level in concentric ring arrays results in wide first null beamwidth (FNBW). The authors propose a pattern synthesis method based on modified Particle Swarm Optimization (PSO) algorithm and Differential Evolution (DE) algorithm to reduce sidelobe level while keeping the first null beamwidth (FNBW) fixed or variable. This is achieved by optimizing both ring spacing and number of elements in each ring of a concentric circular ring array of uniformly excited isotropic antennas. The first null beamwidth is attempted to be made equal to or less than that of a uniformly excited and 0.5 λ spaced concentric circular ring array of same number of elements and same number of rings. The comparative performance of modified Particle Swarm Optimization (PSO) algorithm and Differential Evolution (DE) algorithms based on this particular problem in terms of FNBW, sidelobe level and computational time is also studied.

Keywords

Concentric Ring Array, Differential Evolution (DE) Algorithm, First Null Beam Width (FNBW), Modified Particle Swarm Optimization (PSO) Algorithm.

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B. C. Mahato ¹, G. K. Mahanti ², A. K. Panda ³

Affiliations
1 Department of Electronics and Communication Engineering, Aryabhatta Institute of Engineering and Management, West Bengal, IN
2 Department of Electronics and Communication Engineering, National Institute of Technology, Durgapur, West Bengal, IN
3 Department of Electrical Engineering, National Institute of Technology, Rourkela, Orissa, IN

Abstract

This paper presents a method based on iterative fast fourier technique for placing nulls in prescribed directions by amplitude-only control method in the radiation pattern of scanned linear array of uniformly spaced isotropic antennas with fixed dynamic range ratio of amplitude distribution and minimum peak side lobe level. Two examples have been presented, one with 20 isotropic antennas for placing two nulls and another with 22 isotropic antennas for placing wide null. Dynamic range ratio in both the cases has been fixed at 4.0.The method uses the property that for a linear array with uniform element spacing, an inverse Fourier transform relationship exists between the array factor and the element excitations.

Keywords

Antenna Arrays, Fast Fourier Transform, Null Synthesis, Side Lobe Level, Dynamic Range Ratio.

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