Hybrid elliptic TEM horn with symmetric main beam

The structure of a TEM horn with new plate separation and width profiles is described. It is shown that the combination of a superellipse for the separation function, and a new function for the pate width, results in a horn with nominally frequency-independent properties to beyond 42 GHz. The new separation function has elliptic properties at the throat of the horn, and gradually opens to an almost linear taper.