Dielectric support for high frequency coaxial lines

Claim 1

A coaxial structure comprising a tubular outer conductor; a disc-shaped dielectric support member having an annular periphery the interior surface of said outer conductor having an annular groove for receiving the periphery of said dielectric support member; said dielectric support member having a central opening axially aligned with the longitudinal axis of said outer conductor; at least first and second annular shaped inner conductor sections having their longitudinal axes coaxial with the longituDinal axis of said outer conductor; adjacent ends of said inner conductor sections being positioned on opposite sides of said dielectric support, said inner conductors having conical shaped transitions joining the end surfaces of said adjacent ends to the annular surfaces of said inner conductor sections; each of said end surfaces engaging an adjacent side of said dielectric support member; a third inner conductor member having its longitudinal axis coaxial with the longitudinal axis of said outer conductor; said third inner conductor member being positioned within the central opening in said dielectric member; the diameter of said central opening being less than the diameter of said first and second inner conductor sections; the diameter of said third inner conductor member being less than the diameter of said central opening whereby the outer surface of said third inner conductor member lies a spaced distance from the surface of said central opening to form a hollow annular shaped air gap; means for mechanically joining and electrically connecting the ends of said third inner conductor member to the adjacent end surfaces of said first and second inner conductor sections; the faces of said dielectric member each having an annular shaped compensation groove; said joining means comprising a supporting collar joined to each end surface and extending a small distance into said central opening; the axial length of said annular air gap being greater than the axial thickness of the supporting wall of the dielectric support member in the region of said compensation grooves to provide an acceptable field strength distribution, the grooves in said dielectric support member preventing detrimental influences in the surface of the dielectric support member due to the large air gap formed by the annular grooves and the air gap between the dielectric support member and the third inner conductor member being in series with the dielectric support member to prevent the occurrence of inadmissible peak field strengths.