Antennas on circular cylinders

On the basis of the results obtained by Silver and Saunders [4] for the field radiated from an arbitrary slot in a perfectly conducting circular cylinder, expressions have been derived for the field radiated by a narrow helical slot, with an arbitrary aperture field distribution, in a circular cylinder. The cases of a standing wave and a progressing wave aperture field are given particular consideration. It has also been indicated how a finite width of the slot can be taken into consideration. The results for the helical slot have been used for calculating the field radiated from aU-shaped slot antenna in a circular cylinder. By a procedure similar to the one used by Silver and Saunders, expressions have been derived for the field radiated from an arbitrary surface current distribution on a cylinder surface coaxial with a perfectly conducting cylinder. The cases where the space between the two cylindrical surfaces have the sane characteristic constants and different constants are treated separately. Extensive numerical computations of the field radiated from the slot antennas described here are being carried out, but no numerical results are yet available.