Abstract
A compact sinusoidal tapered slot Vivaldi antenna is designed for X and Ku band applications. The bandwidth of the antenna is improved with two circular stubs before the tapering. A rectangular slot is included before the two stubs to reduce the aperture width of the antenna. The feed line is then terminated with sectorial stub to have better coupling to the slot. The profile of the tapering of slot is designed as sinusoidal variation to have good end fire radiation for the entire frequency range. The simulated single antenna has return loss less than -10 dB in between the frequencies 8.2-20 GHz. A five-element linear array is designed, simulated and prototype model is fabricated. The simulated and experimental results show return loss is less than -7.5 dB for the frequency range of 8.1-20 GHz. The maximum gain of single element and array is 4.6 dBi & 7 dBi respectively. The Co and cross polarization radiation patterns are measured. The designed Vivaldi antenna array is used in electronic warfare and phased array applications.