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This article presents a dual-polarized frequency-scaled ultra-wide spectrum element (FUSE) array on a triangular lattice, precision-machined from an Aluminum block as a self-supporting structure, similar to all-metal Vivaldi arrays reported by the authors in past work. Whereas dual-polarized FUSE arrays normally consist of offset radiator pairs conforming to the ubiquitous square-lattice egg-crate configuration and capacitively coupled at the ends to achieve ultra-wideband operational frequency ranges, this work is novel in that it uses conventional manufacturing to directly machine the dual-polarized FUSE array on a triangular lattice instead. Triangular lattices for dual-polarized wideband arrays are uncommon in the literature and have the benefit of 15.5% reduction in element counts over a square lattice aperture of the same footprint and upper frequency of operation, making this a useful development for applications requiring minimum element counts, i.e., reduced cost/weight. In this article, embedded element performance predictions for the dual-polarized triangular-lattice FUSE array are presented and validated with measurements of a hardware prototype. Results show similar overall grating-lobe-free performance to a square lattice FUSE array of the same footprint and operational frequencies reported in earlier work. The asymmetries of the triangular lattice result in relative performance degradation versus square lattice FUSE arrays as a trade-off to the benefit of reduced element counts for apertures of similar size. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]