High-frequency coaxial attenuator

A probe assembly for measuring parameters of a device under test, comprising:

• a probe tip for contacting the device under test;
• a probe cable having output leads and a predetermined output impedance;
• a high-frequency coaxial attenuator coupled to the output leads of the probe cable, the high-frequency coaxial attenuator including:
• a first coaxial cable portion comprising:
• a first center conductor having a first length;
• and
• a first insulator of the first length formed around the first center conductor, wherein the first center conductor and the first insulator form a first diameter;
• a second coaxial cable portion separated from the first coaxial cable portion by a gap of a predetermined length, the second coaxial cable portion comprising:
• a second center conductor having a second length;
• and
• a second insulator of the second length formed around the second center conductor, wherein the second center conductor and the second insulator form a second diameter;
• a semiconductor material deposited in the gap between the first coaxial cable portion and the second coaxial cable portion, wherein the semiconductor material abuts the first coaxial cable portion at a first side of the gap and abuts the second coaxial cable portion at a second side of the gap;
• and
• an outer conductor, the outer conductor having a first portion formed around an outer periphery of the first coaxial portion, a second portion formed around an outer periphery of the second coaxial portion, and a third portion formed around an outer periphery of the semiconductor material.

A method for making a high-frequency coaxial attenuator, comprising:

• forming a first coaxial cable portion comprising a first center conductor having a first length;
• and a first insulator of the first length formed around the first center conductor, wherein the first center conductor and the first insulator form a first diameter;
• forming a second coaxial cable portion separated from the first coaxial cable portion by a gap of a predetermined length, wherein the forming the second coaxial cable portion includes forming a second center conductor having a second length, and a second insulator of the second length formed around the second center conductor, wherein the second center conductor and the second insulator form a second diameter;
• depositing a semiconductor material in the gap between the first coaxial cable portion and the second coaxial cable portion, wherein the semiconductor material is deposited abutting the first coaxial cable portion at a first side of the gap and abutting the second coaxial cable portion at a second side of the gap;
• and
• forming an outer conductor having a first portion formed around an outer periphery of the first coaxial portion, a second portion formed around an outer periphery of the second coaxial portion, and a third portion formed around an outer periphery of the semiconductor material.