A new rectangular corrugated horn.

We describe a rectangular horn with radiation characteristics similar to those commonly obtained with corrugated horns of circular aperture. The horn described here consists of four identical plates, whose grooves can be obtained (straightforwardly and accurately) by numerical machining. Measurements from 8.7 to 12.2 GHz show that the horn aperture illumination is given to a good approximation by the distribution cos(alpha x)cos(gamma y) in agreement with a asymptotic theory of [7]. Advantages of this horn over a circular horn include simplicity of fabrication, different beamwidths obtained in the two principal planes, and very low level of cross-polarization.