A Novel Circuit-based MIMO Channel Model Considering Antenna Size and Mutual Coupling

With the emergence of numerous antenna and propagation technologies in the upcoming sixth generation (6G) era, the researches on closely linking wireless channel and antennas are challenging. In this paper, a novel circuit-based multiple-input multiple-output (MIMO) channel model considering antenna mutual coupling, size-related antenna equivalent circuit, and channel small-scale fading is proposed. Beyond the fifth generation channel model (B5GCM) is adopted to characterize the wireless channel in the proposed model. Antennas at the transmitter (Tx) and the receiver (Rx) are represented by L. J. Chu's antenna equivalent circuit. In addition, another type of equivalent circuit is introduced to illustrate the necessity of considering an antenna's inductive and capacitive impedances. Through multiport circuit analysis, we obtain a cascaded channel matrix jointly considering the wireless channel, antenna equivalent circuit, and antenna mutual coupling. Non-negligible impacts on statistical properties caused by antenna mutual coupling and size-related antenna equivalent circuit are revealed. Close agreement is achieved between the analytical results and simulation results, verifying the validity of the proposed channel model.