Dual-polarized sliced notch array — ultra-wideband flares with exceptional polarization control

Traditional flared notch arrays for ultra-wideband phased-array applications are known for excellent matching but have very poor polarization control in the diagonal scan plane. The sliced notch array is a variant of the flared notch that by contrast has excellent cross-polarization performance at all scan angles and frequencies for the same LxWxH size array. In this paper we report the first experimental results comparing a traditional dual-polarized flared notch array with a sliced notch array of the same element spacing, aperture height and footprint. Both arrays operate over the same frequency range, roughly 2GHz-21GHz (approx. 10:1 bandwidth) with comparable gain. For a 60-degree scan in all planes, the traditional and sliced notch arrays achieve VSWR <; 3.0 and VSWR <; 2.2, respectively. Near the high frequency limit, for a 45-degree scan in the diagonal plane the traditional flared notch exhibits a complete polarization reversal (cross-pol. 20dB higher than co-pol.), whereas the sliced notch array maintains closer to 20dB of cross-pol. rejection. Measured results are presented that document significant polarization improvements over all scan angles and frequencies.