RESEARCH ARTICLE Side lobe level reduction of thinned concentric elliptical array antenna in vertical and horizontal plane for a desired peak directivity Bitan Misra | Gautam Kumar Mahanti Department of Electronics and Communication Engineering, National Institute of Technology, Durgapur, India Correspondence Bitan Misra, National Institute of Technology, Durgapur, India. Email: misra.bitan2013@gmail.com Abstract This study, describes the design problem of a thinned multiple concentric ellip- tical arrays of uniformly excited isotropic antennas using meta-heuristic opti- mization algorithms; Teaching Learning Based Optimization (TLBO), Crow Search Algorithm (CSA) and Moth Flame Optimization (MFO) algorithm. Two simulations are performed here. In simulation 1, the synthesis of the thinned array structure is presented in the vertical plane at a scanning angle 30  and in simulation 2, the synthesis is performed in the horizontal plane. In both cases, our objective is to minimize side lobe level (SLL) to the extent pos- sible and at the same time maximize the peak directivity to a level higher than the desired value. Here, all the optimization algorithms are applied to obtain the optimum number of switched on and off elements in every concentric ellipse that will meet the above objective. A comparative analysis of all three algorithms is performed using peak directivity, SLL and first null beam width (FNBW) as well as statistical parameters such as mean, SD, best cost function value and run time. To assess the enhanced outcome of the proposed optimiza- tion design comparison is also made with the results of a fully populated con- centric elliptical array antenna (CEAA) for both the cases separately. This paper shows a measure of effectiveness and potential of all the algorithms mentioned above, for designing a thinned concentric elliptical array. KEYWORDS crow search algorithm (CSA), elliptical array antenna (EAA), moth flame optimization (MFO), peak directivity, side lobe level (SLL), teaching learning based optimization (TLBO) 1 | INTRODUCTION With the advancement in wireless communication, antenna engineers are facing various challenges and requirements. In many applications, the need for estimating the speed and direction is prominently increasing, which demands antenna pattern synthesis with high gain and low side lobe level (SLL). Hence, optimization techniques have recently taken center stage in antenna synthesis, where the detailed system design is performed with accuracy and reliability. 1 Among various types of array antennas, the radiation pattern of the elliptical array antenna (EAA) inherently covers the entire space. EAA consists of several elements arranged in the form of an ellipse having an equal or unequal spac- ing between the antennas of the array. 2 Concentric elliptical array antenna (CEAA) is subjected to uniform excitation to obtain a radiation pattern with high directivity but the value of SLL is not satisfactory. To improve the value of SLL Received: 18 November 2019 Revised: 21 May 2020 Accepted: 2 June 2020 DOI: 10.1002/jnm.2785 Int J Numer Model El. 2020;e2785. wileyonlinelibrary.com/journal/jnm © 2020 John Wiley & Sons, Ltd 1 of 16 https://doi.org/10.1002/jnm.2785