A new version of dielectric lined waveguide with low cross-polar radiation

It is shown that while a dielectric lined circular waveguide has a low cross-polar radiation, the condition for precisely zero crosspolar level cannot be met at any real frequency. However, such a condition can be realized if the dielectric lining is transversely slotted at regular intervals, leading to a new structure which has a zero cross-polar level at a certain frequency and can sustain a lower cross-polar level over a wide band relative to the continuously lined waveguide.