Passive microwave direction finding with monobit fourier transformation receiver and matrix coupled antenna

When a military aircraft flying in unknown or hostile air space is discovered by a distant radar apparatus it is often beneficial for the crew of the aircraft to not only be made aware of the occurrence of this radar discovery but to also be appraised of as much information regarding the discovering radar as is possible. Two significant portions of this discovering radar information are the physical location of and the operating frequency of the distant radar apparatus. In addition to the fundamental act of receiving such information concerning the discovering radar apparatus it is desirable that this information become available to the aircraft crew as quickly as is possible and that the information be obtained from as little as one pulse of energy received from a threat signal source. The obtaining of this and other information such as pulse duration and signal strength data in a passive non-signal radiating manner from a distant threat signal is the role of the electronic warfare radio receiver. A passive instantaneous microwave signal frequency identifying and angle of arrival identifying system employing a beam steering multiple element antenna coupled through a Butler matrix to a plurality of simplified Fourier transformation radio receivers wherein unit value or near unit value magnitudes of the Kernel function in the receivers' Fourier transformations are used to elude transformation computation complexity and resulting radio receiver size and cost penalties. Limiting amplifiers, a video signal path and direction finding encoding logic are also employed. Airborne military application of the system in electronic warfare direction finding, radar frequency determination and other activities is included.