A hybrid analytical–optimization framework for sidelobe suppression and beamwidth control in linear antenna arrays

Abstract

This paper presents a novel hybrid analytical-optimization framework for sidelobe suppression and beamwidth control in uniform linear antenna arrays (ULAAs). The primary objective is to achieve significant sidelobe level (SLL) reduction while maintaining a controlled half-power beamwidth (HPBW) through a computationally efficient synthesis strategy. The proposed Enhanced Window-Based Array Synthesis Algorithm (EWASA), also referred to as the Raised Cosine Synthesis with Genetic Algorithm (RCS-GA), is built upon two key innovations. The proposed approach introduces a deterministic spatial shaping mechanism derived from the raised cosine function, originally used in digital communication pulse shaping, and adapts it to the angular domain for radiation pattern control. Unlike conventional tapering techniques that rely heavily on iterative optimization, the desired array response is first constructed analytically using the raised cosine spatial mapping. A closed-form matrix inversion technique then computes the excitation coefficients required to synthesize this target pattern. To further enhance performance, a genetic algorithm optimizes the inter-element spacing, enabling improved sidelobe suppression while maintaining beam integrity. This hybrid approach significantly reduces the dimensionality of the optimization problem and accelerates convergence. Simulation results demonstrate substantial improvements, achieving an SLL of - 38.05 dB and an HPBW of 5.526° for a 15-element array-representing a threefold reduction in SLL and more than 50% improvement in HPBW compared to conventional uniform arrays. The proposed technique maintains a practical excitation dynamic range, and full-wave CST Microwave Studio simulations confirm its practical feasibility. Owing to its computational efficiency, non-iterative core, and precise beam control capability, the proposed method is particularly suitable for high-resolution applications in radar systems, electronic warfare, and microwave medical imaging where interference suppression and beamforming accuracy are critical.