Design method for satellite output multiplexer low‐pass filters exhibiting spurious‐free frequency behavior and high‐power operation

In this article, a design method for high‐power low‐pass filters with wide rejection band is proposed for rectangular waveguide technology. The new filters consist of a classical high‐power E‐plane corrugated low‐pass filter that is cascaded with a quasi‐periodic structure tuned to reject its undesired intrinsic spurious passbands. The new design technique presented here does not impose any limitations on the gap aperture of the original E‐plane corrugated filter. This allows the minimum gap of the corrugated filter to be kept wide which, along with the smoothness and the wide gap of the quasi‐periodic structure itself, enables high‐power TE10 mode operation in the whole structure as the spurious passbands are suppressed. An example will be given in Ku‐band. The resulting prototype will have several kilowatts handling capability and the spurious passbands will be suppressed up to the third harmonic (around 40 GHz). The new design method may have an important practical impact in the design of the low‐pass filter required at the output of the satellite output multiplexers.