Nonperiodic electromagnetic fields in a sectoral horn

A theoretical study is presented of electromagnetic fields excited by a current in a sectoral horn. The analysis is based on Smirnov's (1937) method of the incomplete separation of variables and Riemann's method for solving an equation depending on time and one spatial variable. An exact solution is obtained in the case of the arbitrary dependence of the source. Attention is given to the spatial-temporal structure of various modes, and the features of the transient process in the case of nonstationary excitation of the electromagnetic field are investigated. It is noted that the spatial-temporal structure of the field vector components in the horn is more complex than the mode structure in cylindrical waveguides.