Design of Anti-Phase Feeding Network for W8JK Array Based on In-Phase Power Divider

Double-dipole antennas driven by anti-phase signals (W8JK array) are often used to achieve broadband and good unidirectional radiation patterns. The two dipole elements need a pair of anti-phase signals equal in magnitude. However, realization of anti-phase signals with equal magnitude for the W8JK array is difficult in a planar structure. In this communication, an equivalent feed mechanism of W8JK array is presented. An in-phase power divider is used to realize an anti-phase feeding network for feeding the W8JK array. In order to demonstrate the effectiveness of the designed anti-phase feeding network, an antenna prototype has been designed, fabricated and tested. Experimental results show that the designed anti-phase feeding structure for the W8JK array is effective. The designed antenna provides a 64% measured bandwidth ranging from 6.9 to 13.4 GHz. An excellent endfire radiation characteristic with an F/B ratio better than 17 dB is achieved. The measured gain is better than 4 dBi.