An active antenna unit includes N radio frequency antenna links and L self-interference cancellers, where N is an integer greater than 1, and L is an integer less than or equal to N. Each radio frequency antenna link includes: a transmit channel, a receive channel, a feed network, and an antenna subarray. The N radio frequency antenna links meet at least one of the following: Traces of feed networks of at least two radio frequency antenna links are different; or an isolation assembly is disposed between N antenna subarrays, and is configured to isolate a signal between the N antenna subarrays. In addition, a self-interference canceller is connected between a transmit channel and a receive channel of at least one link, and is configured to cancel a signal that is from the transmit channel and that is on the receive channel of the link.