Filtering Antenna Array Based on Corrugated Vivaldi Elements

This article presents a bandpass filtering antenna array based on corrugated Vivaldi antenna elements and finline waveguides. The low-pass Section of the filtering antenna element is realized by periodically corrugating the inner edges of the Vivaldi elements. The structure can be considered as a periodic transmission line that inherently acts as a low-pass filter. The high-pass Section of the filtering element is realized by surrounding the corrugated slotline with a waveguide. The resulting antenna structure, a finline-fed Vivaldi element, exhibits a wide 1.2–3.1-GHz bandpass response with the upper band-stop rejection exceeding 20 dB up to 6 GHz. The filtering properties are almost independent of the scan angle. The active reflection coefficient is < −10 dB with beam-steering angles within
$\theta = \pm 60^{\circ} $
in the E- and D-planes and < −6 dB in the H-plane. The operation of the filtering antenna element is confirmed by periodic unit-cell simulations and measuring a manufactured 6 × 6 array prototype.