Dual-Polarized Vivaldi Array on a Triangular Lattice

This article presents a dual-polarized Vivaldi array on a triangular lattice. The all-metal ultrawideband Vivaldi features offset radiator pairs that are precision-machined from aluminum stock as a modular tile, similar to earlier reports on more typical all-metal square-lattice Vivaldi arrays. The intent of this work is to validate the embedded element performance of the dual-polarized triangular-lattice Vivaldi, comparing one-to-one with results for a similarly sized dual-polarized all-metal Vivaldi array on a square (egg-crate) lattice, reported previously. The triangular-lattice Vivaldi array is optimally sampled for grating-lobe-free scans with a potential 15.5% reduction in element count compared to a corresponding optimally sampled square-lattice array of similar size. As such, the footprint of the manufactured triangular-lattice Vivaldi array is roughly 8% larger than the square-lattice array, yet has 7% fewer elements. Infinite array predictions are presented and shown to compare favorably with previous findings for the square-lattice Vivaldi array, noting minor performance compromises. Wideband and wide-scan simulations are validated with measurements of prototype hardware, demonstrating that embedded element performance of the triangular-lattice array correlates well with modeling predictions. All told, the triangular-lattice array has similar capability to the square-lattice Vivaldi array in a more efficiently sampled aperture.