Low passive intermodulation coaxial connector test interface

A coaxial RF test connector having a center axis and an opening configured to receive a compatible coaxial connector in an inward direction, the coaxial RF test connector comprising:

• an inner conductor and an outer conductor, both arranged coaxially to a center axis of said RF test connector,
• a circularly shaped contact spring held within a groove of the outer conductor,
• wherein the contact spring includes a base and a plurality of arc-shaped contact fingers extending from the base with gaps between individual contact fingers,
• at least one of the contact fingers having a first contact section configured to contact the outer conductor of a compatible coaxial connector in a direction radial to the center axis,
• a second contact section between the base and the first contact section, the second contact section being configured to contact a sidewall of the groove, and
• an insulation disc of a dielectric material between the second contact section and the sidewall.