INTERFEROMETERS

摘要

It is known to use Bragg's law to determine the angle at which a plane wave of electromagnetic radiation is incident on a pair of detectors once the frequency of the radiation, the spacing of the detectors and the phase difference of the signals arriving at the detectors are known. However, the angle calculated can be ambiguous as the phase difference may have more than one value. Described herein is an interferometer arrangement (30) including an antenna array (32) which receives radiation from a plane wave (34) emitted by a transmitter, the radiation being incident on the array at an angle (theta ). The array (32) includes a plurality of antennas which provide outputs signals (36, 38, 40, 42) to a switching unit (44). The switching unit (44) selects pairs of signals and passes them to a processor (46) for processing. The processor (46) produces an output signal (48) which unambiguously indicates the value of the angle (theta ).