Corrugated horn design

In a corrugated horn the surface of the inner part is corrugated. The corrugations are typically axial (that is, in the direction of the horn axis) or radial (i.e., perpendicular to the axis). The depths of the corrugations usually vary between λ/4 and λ/2, where λ is the wavelength of the electromagnetic field at the design frequency. An example of a corrugated horn is shown in the picture below.

Where is a corrugated horn used?

The main advantage of a corrugated horn is its capability to radiate a field with very low cross polarisation. This means, in other words, that the field lines in the horn aperture are almost parallel. Corrugated horns are therefore employed in application in which it is important to separately transmit (or receive) two orthogonal polarisations.

When is a corrugated horn used?

Corrugated horns are typically used as feeds for reflector antennas where low cross polarization is required. With a corrugated horn the low cross polarisation can also be maintained over a very large frequency bandwidth. In offset reflector configurations, the geometry itself introduces cross polarisation in the radiated far field. Hence, for such offset configurations it is particularly important to use a feed horn that radiates a purely co-polarised field.

Which tool do you use to design a corrugated horn?

CHAMP 3D has a dedicated wizard for the design of radially as well as axially corrugated circular horns. The analysis is extremely fast since Mode Matching and Body of Revolution Method of Moments is used. The modeling capability of CHAMP 3D has been validated by measurements over many years through widespread use among our customers.

The fast analysis time of CHAMP 3D makes it possible to improve a horn design through optimisation. A general-purpose software tool, on the other hand – which is not dedicated to the analysis of corrugated circular horns – will be too slow and a similar horn optimisation with such a tool is not possible.

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