In computation of radiation performance of multi-port antennas especially in multiple-input multiple-output (MIMO) antenna systems total active reflection coefficient, TARC, relates the total incident power to the radiated power. The total active reflection coefficient (TARC) is the square root of the sum of all incident powers at the ports minus radiated power, divided by the sum of all incident powers at the ports of an N-port antenna. The TARC is a function of frequency. With this definition we can characterize the multi-port antenna’s frequency bandwidth and radiation performance. TARC can be computed directly from the scattering matrix for different excitations.
where: