Coaxial waveguides
Passive microwave circuits - Metal waveguides

The cross-section of a coaxial guide can be circular, square or even rectangular (figure 11 ). The central conductor is supported by the dielectric, which completely fills the space between conductors; the dielectric also ensures centering. If the dielectric medium is air, dielectric shims (washers), arranged at regular intervals, are used to support the central conductor.

The coaxial guide, like the rectangular and circular guides, is a non-radiating guiding structure, since the electric and magnetic fields are confined within the region between the two conductors.

Since the conductor contour is multiply connected, the fundamental...