Analysis of the field within bounded wave simulator with a large test object in the working volume

A bounded wave simulator is an efficient broad bandwidth illuminator and has been widely used in simulating the EMP pulse propagating in free space with a plane wave model. A test object in the working volume will cause field distortion. In this paper, the FDTD method is used to calculate the field distributions when a test object is situated in the bounded wave simulator or in a radiated plane wave. The errors of the field distribution according to the different ratio of the test object dimensions to the height of the working space is calculated and compared with the field in free space, especially the tangential H field component on the conductor surface. The method to determine the maximum test size in an EMP simulator is corrected based on our discussion. The advantage of the new method is that the results are more reasonable than before.