A test setup for power measurement of a fast switching active antenna array with a beam switching time lower than one microsecond is described. The test setup includes at least two detector modules for detecting a signal transmitted by the fast switching active antenna array and a power sensor module for measuring the power of at least one signal received. The power sensor module has an analog-to-digital converter circuit for converting an analog signal into a digital signal. Each of the detector modules includes at least one antenna via which at least one signal transmitted by the fast switching active antenna array is received. The at least two detector modules are positioned in at least two predefined main radiation directions of the fast switching active antenna array. Each of the detector modules has a rise time, the rise time being lower than the beam switching time of the fast switching active antenna array.