Wideband, Low-Profile, Dual-Polarized Machined-Metal Array on a Triangular Lattice

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.