Coaxial connector

A coaxial connector (300) comprises an outer contact (314) having a mating end (360) configured to be mated to a mating connector, and a terminating end (362) configured to be mounted to a circuit board (302). A central cavity (364) extends between the mating end and the terminating end. A center contact (310) is disposed in the central cavity and is configured to be terminated to the circuit board. A circuit board mount (316) is coupled to the terminating end and is configured to mechanically and electrically connect the outer contact to the circuit board. A dielectric insert (312) is received in the central cavity, and the dielectric insert has a bore (340) that receives and holds the center contact. The dielectric insert has structural features (346) extending axially along an exterior of the dielectric insert, and air gaps (348) are defined between the structural features. The structural features engage the outer contact (314) to secure the dielectric insert (312) in the central cavity (364).