Indented antenna array for full-duplex repeater

An indented antenna array is proposed for its low return loss and mutual coupling which may help to reduce the feedback in two-way full-duplex repeater. The essential idea is to take advantage of the different phase delays between the transmitting return and receiving paths created by the indention. An indention with linear progressive phase delays can make transmitting returns destructively combined while the receiving paths constructively combined. For the same reason, the antenna array front to back ratio can be improved as the aperture is no longer symmetrical toward both front and back sides. The reduction of transmitting to receiving (T/R) leakage due to the improved return loss and the increase of isolation due to a lower mutual coupling make these arrays ideal for full-duplex repeater applications. An eight-element indented dipole array is designed and simulated in ADS. The results demonstrate 18dB T/R isolation and at least 7dB front to back ratio improvement, which implies 14dB improvement in mutual coupling.