Dual-Polarized Metal-Flare Sliced Notch Antenna Array
Rick W. Kindt, John T. Logan
Abstract
This article presents a dual-polarized metal-flare sliced notch antenna (SNA) array comprising metallic Vivaldi flares “sliced” by air gaps. Aside from the slice gaps in the flares (supported with foam sheets in the array build), the SNA is an exact duplicate of a conventional all-metal Vivaldi array, against which the SNA is presented directly in a one-to-one comparison to isolate the effect of slicing on dual-polarized radiator performance. The SNA has very similar capabilities as the Vivaldi in all metrics (match, gain, port isolation, and bandwidth), except that the SNA demonstrates lower cross-polarization (cross-pol) across all scan angles and frequencies. Both arrays are optimally sampled and have excellent matching from 2.6 to 21.2 GHz with zero scan blindness out to wide angles. For this demonstration, uniform slices are introduced in the flares to satisfy a single design criterion of -10 dB cross-pol (relative to copolarized fields) for a 45° scan cone at all frequencies, culminating in a peak SNA cross-pol improvement of 35 dB (relative to the reference Vivaldi array). Infinite array predictions are followed up by measurements on a 256-port prototype aperture. This work demonstrates that the slicing technique can be applied to effectively mitigate high cross-pol in dual-polarized Vivaldi arrays without inhibiting other performance metrics.