Test system as well as method for over-the-air testing

A test system for over-the-air testing, the test system comprising:

• a measurement antenna, the measurement antenna being a multiple polarization antenna that is configured to measure signals with at least two different polarizations, the measurement antenna having a first measurement port and a second measurement port via which a first polarized signal portion and a second polarized signal portion are provided, respectively, wherein the first polarized signal portion is one of a horizontally polarized signal portion or a vertically polarized signal and the second polarized signal portion is the other one of the horizontally polarized signal portion or the vertically polarized signal;
• a power combiner having a first input port and a second input port, the power combiner being directly connected via the first input port to the first measurement port of the measurement antenna for receiving the first polarized signal portion;
• and
• a mixer being connected to the measurement antenna via the second measurement port for receiving the second polarized signal portion, the mixer having an output port connected to the second input port of the power combiner, the mixer being configured to shift the frequency of the second polarized signal portion so that frequency spectra of the first and second polarized signal portions to be received by the power combiner are spaced from each other,
• wherein the power combiner is configured to receive the first polarized signal portion from the measurement antenna and to receive the second polarized signal portion from the mixer, the power combiner further configured to combine the first polarized signal portion and the second polarized signal portion to form a combined signal having two bands that relate to the horizontally polarized signal portion and the vertically polarized signal portion.