UNIFORM GAIN POWER-SPECTRUM ANTENNA-PATTERN THEOREM AND ITS POSSIBLE APPLICATIONS

For certain applications in radio astronomy, viz. radio spectrographs, spectrum monitoring etc., only the amplitude power spectrum coverage within an angle of observation could be of interest. Ideally, the antenna structures of such instruments should illuminate this covering angle with a fixed uniform gain. This might be achieved using a combination of dipole antennas, a single vertical dipole, a loop antenna etc., but are subjected to limited bandwidth. This limitation could be overcome if many electrically-identical wideband antennas are positioned across the perimeter of a circle lying in the horizontal plane such that the antennas' adjacent half power beam angles touch each other. It has been theoretically observed that if two identical antennas are positioned at an angle with respect to one-another in such a way that their adjacent half power beam angles coincide, then if the amplitude power spectrums of the two are added, the result is effectively an amplitude power spectrum obtained from a single antenna having an uniform gain and uniform signal to noise ratio within the angle subtended by them. This angle also happens to be equal to the half power beamwidth of the individual antennas. A proper design using frequency independent antennas might possibly result to an user specified uniform amplitude power spectrum gain coverage across any required angle, with a theoretically unlimited bandwidth. More number of identical antennas might be positioned in similar fashion for extending the angular coverage.