Method for increasing the mode density in a reverberant screened room

A method for increasing the mode density in a screened room is introduced. The method relies on the use of binary pseudo random phase reflection gratings on the walls of the room. These gratings have geometries based on binary sequences. A measure S² is introduced which predicts how well each sequence will succeed in scattering energy. It is shown that, for a given set of room dimensions, there is a correlation between S² and mode density, and an optimal sequence has been found using the measure. Finally, using an impulsive excitation, the time domain response inside the room is examined. It is shown that, without a grating, the directions of the electric and magnetic fields do not vary greatly with time, whereas the inclusion of a grating produces field directions which are much more varied