A concept of modulated scattering antenna array (MSAA) is proposed based on the modulated scattering technique. The antenna array is composed of one regular antenna element and several modulated scattering elements (MSE). The regular antenna has its RF front-end circuit, but the MSA has not. The configuration of the array antenna is very simple because only one branch of the front-end circuit is required. This paper reviews the previous studies on the MSAA as multi-antennas in a multi-path transmission environment, and mainly introduces a numerical simulation of the MSAA in MIMO transmission. It is shown by both numerical and experimental investigations that the MSAA is capable of acting as multi-antennas for improving diversity gain and increase the channel capacity. It is demonstrated that the MSAA is suitable to the mobile handset applications where the space and the cost are strictly limited due to its simple configuration.