From Curved to Planar: Enabling Large-Spacing Phased Array Antenna to Achieve Grating- Lobe-Free Wide-Angle Scanning

The phased array antenna (PAA) scanning faces challenges from element spacing requirements to prevent grating lobes, conflicting with the trend toward higher frequencies and cost reduction. Addressing this, this article presents a large-spacing planarized curved array (LSPCA) technology that enables PAAs to achieve grating-lobe-free wide-angle scanning with large spacings. Inspired by the radiation characteristics of Bessel beams in curved arrays, this technology maps a curved array into a large-spacing planar configuration equipped with heterogeneous beam elements (HBEs), inheriting the superior scanning capabilities of the curved format. The study provides theoretical foundations, design methodologies, and experimental validation for this technology. It details the mapping process from curved to planar arrays, examines its wideband characteristics, and evaluates the impact of critical parameters on performance. Experimental validation with two LSPCA configurations confirms the effectiveness of this technology: a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 8$ </tex-math></inline-formula>-element array demonstrates ±75° scanning with an average element spacing of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.06\lambda $ </tex-math></inline-formula> and sidelobe levels (SLLs) below −5 dB, while a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 16$ </tex-math></inline-formula>-element array extends this to ±80° with an average spacing of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.27\lambda $ </tex-math></inline-formula> and SLLs below −8 dB. Demonstrating exceptional grating-lobe-free wide-angle scanning at large spacings and leveraging formulaic design rather than complex optimization, this technology offers a promising solution for large-spacing arrays.