Abstract: A measurement device (100) for measuring antenna characteristics of an antenna under test (150, AUT), the AUT having a radiating element (160), the measurement device (100) comprising an exterior surface (110), where a measurement aperture (120) is formed in the exterior surface, and a repetitive structure (130) is arranged on the exterior surface, the repetitive structure (130) comprising a plurality of protruding conductive elements (135) arranged to surround the measurement aperture (120) and to define a passage (140) into the measurement aperture (120), the repetitive structure (130) being configured to attenuate electromagnetic signal propagation in a frequency band past the repetitive structure (130) while allowing propagation via the passage (140).