6. Standard lines

Coaxial line

The coaxial line is by far the most widely used (figure 6 ). It consists of a conductive cylinder with a circular base and radius r ₁ , which forms the inner conductor, and a tube concentric with the inner conductor. This tube, with inner radius r ₂ , forms the second conductor. The space between the two conductors is filled with a dielectric of constants ε, µ. The dielectric is very often polyethylene, whose relative permittivity ε _r = ε /ε ₀ is equal to 2.25.

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