An antenna interface unit (AIU) for providing low power loss, fault tolerant connectivity between multiple transmitters and an antenna, and between multiple receivers and the antenna. The antenna interface unit also eliminates single point failures in a transmit/receive (T/R) mechanism. The antenna interface unit includes (a) a power combiner/splitter connectable to the antenna; a receive channel connected to the power combiner/splitter; and a transmit channel connected to the power combiner/splitter. The transmit channel is a different channel from the receive channel. The receivers are connectable to the antenna via the receive channel and through the power combiner/splitter. The transmitters are connectable to the antenna via the transmit channel and through the power combiner/splitter. Different variations of the receive channel and the transmit channel are provided by using different combinations of power combiners and power splitters.