The diagonal horn as a sub-millimeter wave antenna

The far-field radiation pattern of a diagonal horn has been calculated by aperture integration. The radiation patterns for a 4 x 4 diagonal horn array, measured at 100 GHz, agree very well with the theoretical predictions. The aperture electric field was also expanded into Gauss-Hermite modes. The results indicate that the fraction of the power radiated into the fundamental Gaussian mode is about 84 percent. About 10 percent of the power is radiated in the cross-polarized component.