Design of high gain, low side-lobe level base station array antenna for 5g-sub 6 ghz communication system

Abstract

In this paper, a high-gain and low side-lobe level array antenna is proposed for 5G sub-6 GHz base station applications operating in the C-band. The antenna is based on a modified magneto-electric (ME) dipole design, comprising two triangular metallic plates, two rectangular metallic plates, grounded vias, an L-shaped probe, a ground plane, and a microstrip feed line. A single antenna element, with overall dimensions of 96 mm × 96 mm × 2.4 mm (approximately 1.55λ₀ × 1.55λ₀ × 0.04λ₀ at 4.9 GHz), demonstrates a wide impedance bandwidth ranging from 4.50 GHz to 5.06 GHz with a reflection coefficient (|S₁₁|) below –10 dB, and achieves a peak gain of 3.1 dBi. A 1×8 linear array of ME dipole elements is developed using uniform in-phase and equal-amplitude excitation. This configuration yields a high peak gain of 13.8 dBi; however, it also results in relatively high side-lobe levels, reaching –12.9 dB. To address this limitation, a trapezoidal amplitude tapering technique is applied to the excitation of the array. The simulated results indicate a significant improvement, achieving a side-lobe level below –28 dB while maintaining a high gain of 13.6 dBi.