Three-Element End-Fire Linear Arrays (Super) Directivity and Gain Optimization

This paper presents the results of the optimization of two three-element end-fire linear arrays based on straight- and bent-electrical dipoles, respectively. To achieve a compact architecture, the inter-element distance is fixed to 0.12$\lambda$ with $\lambda$ the wavelength calculated at the operation frequency (850 MHz). The array complex excitation coefficients have been optimized to achieve either maximum directivity or maximum gain. The synthesis procedure is based on the optimization of the directivity or gain formulas considering the array factor and the active element patterns. The numerical results have been validated by 3D full-wave electromagnetic simulations. The maximum directivity is equal to 10.0 (gain 2.91 dBi) and 9.83 dBi (gain 3.67 dBi) in the case on the straight- and bent- electrical dipole based arrays, respectively. Instead, the maximum gain is equal to 6.81 (directivity 8.84 dBi) and 7.85 dBi (directivity 9.19 dBi), respectively.