20GHz-Band Low Backlobe Vivaldi Endfire Antenna Array for Digital Beamforming Transmitter Antenna Module

In this paper, we propose a 20GHz-band low backlobe Vivaldi antenna array for digital beamforming (DBF) transmitter module. The proposed endfire antenna array can be directly integrated with DBF transmitter module. With the low backlobe characteristics, the influence on radiation pattern from transmitter module behind antenna can be eliminated. By using two corrugated slits on both edge sides, the front-to-back (F/B) ratio of antenna element can be improved beyond 20 dB in simulation. 4-element Vivaldi endfire antenna array is fabricated and measured. The measurement result of proposed antenna array has a good agreement with the simulation result.