Measurement Uncertainty in Multipath Simulators Due to Scattering Within the Antenna Array—Theoretical Model Based on Mutual Coupling

Multipath simulators are attracting much interest as tools for mobile terminal tests. The equipment uses an array of antenna elements placed around the test object, and signals to the test object are distributed over the array in various ways. The array antennas cause unwanted scattering, resulting in increased disturbance level in the room, with consequences to the measurement uncertainty. In this letter, a quantification of the measurement uncertainty is found through a study of the mutual coupling between the array elements. A statistical approach is applied, and an expression for the standard deviation in transferred power is derived. Measurements are presented that verify the expression.