A test probe (10) for contactlessly measuring the electromagnetic properties of a radio unit (20), in particular an antenna unit, having a hollow conductor (1) for transmitting electromagnetic waves, a filling element (2) which is disposed in the hollow conductor and made of a dielectric material, a lens element (3) which is disposed on the end face of the hollow conductor (1) and made of a dielectric material for coupling electromagnetic waves into the hollow conductor (1), and a contact portion (4) which is disposed on the hollow conductor end opposite the lens element (3) and which serves to decouple a measurement signal.