Evaluation of diversity antenna characteristics in narrow band fading channel using random phase generation process

To assess the performance of a diversity antenna in a fading environment, it is necessary to know the incoming field distribution in amplitude and phase, for each direction of arrival. Some information is available for amplitude distribution of the incoming field for various environments but, to our knowledge, almost no information has been given on phase distribution. We propose an algorithm which generates a random phase variable with time, and does this for every direction of arrival. Incident plane waves are generated with constant amplitude and time varying phase for all space angles; the received signal at the antenna port is derived from the scalar product of the incident field vector and the 3D complex radiation pattern of the receiving antenna. For the field generation algorithm, the result acts as multipath fading at the reception point. The statistical parameters of the simulated faded signal correspond to a narrow band multipath fading channel. In order to evaluate our model, a mode stirred reverberation chamber is used, the statistical parameters of which correspond to a narrow band fading channel. A diversity antenna is tested inside the mode stirred reverberation chamber and its parameters (correlation coefficient, difference in mean received power by diversity branches and diversity gains for diversity combining methods) are evaluated and compared with the proposed simulation model. The agreement obtained between simulation and measurement make the proposed method a short way for diversity parameter evaluation in narrow band fading channels.