Improved High Gain Vivaldi Antenna Design for Through-wall Radar Applications

This paper presents a compact, low cost, high gain Ultra wideband (UWB) Vivaldi antenna convenient for Through-wall Radar (TWR) applications. This antenna, designed on low cost FR-4 substrate with thickness 0.8 mm has an operating frequency range from 1.9 GHz to 12 GHz. The proposed antenna shows a stable radiation pattern within the operating range and a gain greater than 6 dBi in the frequency range 2.2 GHz - 6 GHz with a maximum gain of 8.2 dBi and directivity of 9.04 dBi at 4.5 GHz which is ideal for Through wall Radar applications. Initially a compact and wideband Vivaldi antenna with exponentially tapered slot is designed and fabricated. Corrugations are added along the length of the antenna and periodic grating elements are inserted at the opening end of the exponential slot resulting in significant increase in gain, improved directivity and better impedance matching even at lower frequencies of the operating band. The fabricated antenna is tested and the measurement data corroborates the simulation results from Computer Simulation Technology Microwave Studio (CST-MWS).