Multiband Antipodal Vivaldi Antenna for Non-Contact RADAR Sensing Applications

This paper presents a multiband antipodal end-fire Vivaldi antenna designed for non-contact radar sensing and material characterization applications. The proposed antenna incorporates semi-elliptical corrugations and periodic circular slot perforations to achieve multi-band resonance across key radar frequency bands, including S, C, X, and Ku. A ground pad is integrated to enhance impedance matching, while circular director elements improve gain in the end-fire direction. The proposed antenna achieves peak gains of 7.06 dBi at the S-band (3.0 GHz-4.0 GHz), 9.78 dBi at the C band (5.0 GHz – 7.5 GHz), 10.2 dBi at the X band (8.0 GHz-12.0 GHz), and 11.5 dBi at the Ku band (12.0 GHz – 18.0 GHz), demonstrating its suitability for multiband RADAR sensing applications.