An <i>X</i>-Band Through <i>Ka</i>-Band Thinned All-Metal Vivaldi Phased Array
Mohamed A. Elmansouri, Gaeron R. Friedrichs, Ljubodrag B. Boskovic, Dejan S. Filipović
Abstract
The design and performance of a thinned <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8 \times {8}$ </tex-math></inline-formula> singly polarized all-metal Vivaldi phased array are presented. A genetic algorithm (GA)-based optimization is employed to demonstrate the feasibility of thinning this small element count, ultrawideband connected Vivaldi array. A 50% thinning factor, obtained by terminating 32 elements, is considered and the thinning configuration is optimized with multiple objectives to maximize total efficiency at the low-frequency end and minimize sidelobe level (SLL) in the E- and H-planes at the high-frequency end. Pattern multiplication with embedded element patterns and simulated finite array S-parameters are utilized for efficient optimization. A prototype operating over 10–35 GHz is fabricated and measured. Experimental and numerical results show that the thinned phased array exhibits a reduction of peak SLL >10 dB in two principal planes, aperture efficiency >50%, and total losses <2.1 dB. The array maintains good performance as it scans up to 45°. Although a small array size is considered herein, the presented analysis and results pave the way for the thinning of large tightly coupled arrays, effectively reducing the number of required transmit/receive (T/R) modules while achieving a desired far-field improvement.