Dual-Polarized Directive Ultrawideband Antenna Integrated With Horn and Vivaldi Array

A novel ultrawideband dual-polarized H-plane horn antenna incorporated with a Vivaldi array is proposed. Aiming at ultrawide low-frequency applications that require dual-polarization with a compact shape, the proposed antenna employs an all-metal shared aperture structure. Different from the conventional dual-polarized horn where dual polarization is achieved using two orthogonal modes of the same waveguide, the proposed antenna uses two different types of transmission line for feeding: rectangular waveguide for vertically polarized (VP) H-plane horn antenna, and slot line for horizontally polarized (HP) Vivaldi antenna array. The Vivaldi slot significantly increases the HP bandwidth compared to the typical dual-polarized horn antennas, and does not disturb the VP radiation pattern. The proposed antenna has a measured -10 dB impedance bandwidth of 103% for HP mode, and 77.5% for VP mode. The measured peak gain for HP is 13.0 dBi and 14.3 dBi for VP. The simulated and measured results are in good alignment.