This invention relates to a system for the detection of radiation emanating from a source, such as objects illuminated by sunshine, and, more particularly, to a system incorporating a microwave antenna array for the detection of radiated power in the microwave portion of the spectrum, the system including correlation and Fourier transform circuitry coupled to the antenna array by a common microwave feed for reduced complexity of the microwave structure.
Various types of devices are employed for sensing radiation emmited by distant objects. For example, devices employing detectors of infrared radiation are used in detecting the presence of radiators of infrared radiation. In radio astronomy, RF (radiofrequency) telescopes employing an array of antennas detects the presence of RF energy emitted by distant stars.
In the case of systems which are constructed for the detection of energy in the microwave portion of the spectrum, considerable microwave structure, in the form of numerous waveguide components, has been employed to connect various antenna elements in an array of such elements to process microwave signals received by the antenna elements. The signal processing has involved the amplification of signals of various microwave channels, as well as combination of the signals of the various elements to obtain directional information about the source of radiation.
A problem arises in that the microwave structure which interconnects the various antenna elements introduces excessive size, weight, and complexity to the microwave radiometer. Such complexity is manifested in numerous waveguides which interconnect the antenna elements with signal processing equipment.