Coupling and scattering of a cylinder with four short dipoles in a four parallel wire system

An important anechoic chamber problem is to design a four-parallel-wire anechoic chamber at VHF frequencies which produces transverse electric and magnetic (TEM) waves which are close to plane waves of free space. An important associated problem is the problem of determining the electromagnetic scattering and coupling that occur between the four-wire system and a scattering object which is located in the four-wire anechoic chamber. A cylinder with four short attached dipoles is used as a scattering object. The coupling that occurs between the four parallel wires from which the antenna system is constructed, the short dipoles which are attached on the cylinder, and the cylinder which is used as a scatterer is analyzed through the use of a method-of-moments computer program called the numerical electromagnetics code (NEC). The variations of the induced currents on the four short dipoles are obtained when the cylinder with these short dipoles has different angles of orientation with respect to the incident direction of the four-parallel-wire TEM wave