Asymmetrical trough waveguide antennas

Line source radiators of the leaky wave type may be constructed readily with trough waveguide, which consists of a rectangular trough containing a symmetrically located center fin. Two types of such radiators are investigated: a continuously asymmetrical form suitable for near endfire radiation, and a periodically asymmetrical design permitting radiation through broadside. The propagation characteristics of the leaky wave on the continuously asymmetrical structure are determined theoretically by means of a transverse resonance procedure, and comparison is made with measured values. The influence of finite center fin thickness is also accounted for. Designs and radiation patterns are presented for a typical antenna of each type.