High Gain Vivaldi Antenna for Radar and Microwave Imaging Applications

An Ultrawideband (UWB) high gain compact Vivaldi antenna with end fire radiation patterns is presented for radar and microwave imaging applications. The antenna is operating for 2.9GHz to more than 11GHz with -10dB impedance bandwidth and is designed on low cost FR4 substrate of thickness 0.8mm. While designing the proposed antenna, initially a compact exponential tapered slot Vivaldi antenna is presented for wide impedance bandwidth performances. Further, the Vivaldi antenna is modified by incorporating corrugations on the edges of exponential metallic flaring section and some periodic grating elements consists of small metallic strips on the slot area, which results in improvement in gain significantly along with increased directivity and lower frequency band coverage. The proposed antenna shows nearly stable endfire radiation patterns throughout the frequency range. The surface current distributions and input impedance plots are presented to understand the antenna mechanism.