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Horn Antennas

June 17th Fact-of-the-Day

Horn antennas are fundamentally waveguides that expand in height, width or both to some finite length. The maximum possible gain is determined by the area of a horn aperture in wavelengths, but that gain is not achieved unless everything is right. Discontinuity at the junction between a uniform section of waveguide and a flared section causes a number of electromagnetic modes to be excited in a horn throat. However, the higher-order modes are attenuated sufficiently to have negligible level at the mouth of a horn where radiation occurs if a horn flare angle is not too great. Small flare-angle horns have highly-predicable gains and relatively-simple radiation patterns with few side lobes. Large flare-angle horns have less gain and complex radiation patterns with many lobes. ©2005 Martek International All rights reserved.


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