Method of MIMO Channel Estimation Between Parasitic Antenna Arrays

This paper proposes a channel estimation method between parasitic antenna arrays that have no radio frequency (RF) frontends. The multiple-input multiple-output channel exceeding the number of the RF frontends can be defined if the parasitic antennas are used in both the transmitting and receiving array antennas. The channel between parasitic antenna arrays can be estimated by varying the tunable reactance elements at the parasitic antennas. Based on the simulation and experiment, the channel estimation is demonstrated and its accuracy is studied.