Abstract: An in-line coaxial circuit assembly having a first portion with a first electrical connector interface on a first end and a second portion having a second electrical connector interface on a second end. The first portion and the second portion adapted to couple together along an outer wall of at least one of the first portion and the second portion. A cylindrical outer conductor section coaxial with the outer wall may be formed in at least one of the portions. The coupling of the first portion and the second portion forms an enclosed cylindrical PCB chamber between the outer conductor section and inner conductor or outer wall, if present. A PCB may be positioned within the PCB chamber, the PCB coupled to the inner conductor through a slot in the outer conductor section, if present.