Monomode microwave-radiating horn for radar or telecommunication - has progressive and continuous decrease of slope along axis from 90 degrees or less towards zero at opening

摘要

The horn (8) is fed from a waveguide (9), and the profile of its internal walls (10) along a longitudinal section parallel to the axis of wave propagation has a slope which decreases continuously from 90 deg. or less at the input (11) to approximately zero at the aperture (12). The slope falls off rapidly in the region where only the fundamental mode is propagated. In regions where higher modes are liable to be propagated, the slope decreases slowly enough for their excitation to be very weak, giving a field distribution of quasi-constant phase over a considerable frequency band. Such a tulip profile can form either a sectoral horn in the E or H plane, or a horn of revolution about the axis of propagation.