A Low Sidelobe Ultrawideband 1D Monopulse Antenna Array for Direction Finding

In this paper, an ultra broadband one-dimensional monopulse antenna array fed by sum-difference network is presented. The Vivaldi antenna used to construct array ranges from 6 to 12 GHz. The sum-difference network is designed using 3dB orthogonal bridge, a wide-band multi-section 90 degree phase shifter, and two 1-to-8 multi-section unequal broadband Wilkinson power divider. The measured results of the monopulse indicate that the sidelobe level of the sum beam is less than -20dB and the null depth is below -20dB.