A radar apparatus including a transmit/receive antenna having a plurality of channels, a comparator coupled to the antenna channels for providing receive signal sum and difference channels, a radar receiver, a coupler for coupling the sum and difference channels to the radar receiver, a radar transmitter for providing a signal to be transmitted, a coupler for coupling the transmitter to a cross-channel port of the comparator, and an adjuster for adjusting a phase length of at least one antenna channel so that when the apparatus is transmitting, the transmitted signals from the antenna channels have a specified relative phase relationship.