Radio frequency antenna with granular or powder insulating material and method of making the same

A radio frequency antenna assembly adapted for use in radio frequency vehicle exhaust control and sensor system and comprising:

• a coaxial cable including a coaxial conductor;
• a center antenna including a distal end coupled to a distal end of the coaxial conductor of the coaxial cable;
• an outer sleeve surrounding and spaced from the center antenna and defining a cavity between the center antenna and the outer sleeve;
• and
• a granular or powder insulating material filling the cavity between the center antenna and the outer sleeve.

A method of making a radio frequency antenna assembly comprising the steps of:

• a) providing a coaxial cable with a coaxial center conductor;
• b) providing a center antenna;
• c) coupling a distal end of the center antenna to a distal end of the coaxial center conductor;
• d) providing and sliding an outer sleeve over the center antenna into a relationship surrounding and spaced from the center antenna and defining a circumferential cavity between the outer sleeve and the center antenna;
• e) securing a first end of the outer sleeve to the coaxial cable;
• f) providing and filling the cavity defined between the center antenna and the outer sleeve with an insulating granular or powder material;
• g) providing a seal material and covering a second end of the outer sleeve with the seal material for sealing and retaining the insulating material in the outer sleeve;
• and
• h) bending the center antenna and the outer sleeve into a desired final shape.