High performance smooth-walled horns for THz waveguide applications
Thomas Tils, Axel Murk, David Rabanus, C.E. Honingh, Karl Jacobs
Proceedings of 16th International Symposium on Space Terahertz Technology
For the coupling from free space to waveguide corrugated horns are presently the optimum choice. Currently the extension of the waveguide technology towards THz frequencies, e.g. with silicon micromachining techniques, looks very promising, which increases the demand for THz horns. The HIFI project has shown that even at submm frequencies it is not easy to manufacture reliable corrugated horns for cryogenic applications. For small corrugations it is difficult to avoid fluid inclusions in the corrugations during electroforming. In addition experience has shown that dust or small metal particles can
easily settle in between the corrugations and are very difficult to remove. Smooth-walled horns do not have these disadvantages.
We will present measurements of a prototype smooth-walled horn
for 756-924 GHz. The horn is designed by C. Granet  and
manufactured by RPG . The measurements were done at 800,
840 and 860 GHz with an AB-mm vector network analyzer at the University of Bern. We have also simulated the performance of the horn in CST Microwave Studio . The simulation results are in a good agreement with the measured data. With the same measurement setup we measured a corrugated horn for the HIFI band 2 Mixer Unit. We conclude that we can replace the corrugated horn by a properly designed smooth-walled horn without significant loss of performance. This is an important step towards building THz waveguide mixers.
Back to References