Abstract: A frequency tunable microwave bandpass filter comprises a resonator, including: a cavity with conducting wall substantially cylindrical with axis Z having height H, and partially closed at both ends; and a dielectric element inside the cavity. The resonator resonates at two perpendicular polarizations having distributions of electromagnetic field in the cavity deduced from each other by 90° rotation. The element rotates about an axis substantially perpendicular to axis Z, between a first and second position. The element comprises a first end wherein: in a first position the element is disposed substantially in a plane perpendicular to axis Z and the centre of the first end is disposed at a height in the cavity corresponding substantially to an electric field minimum; and in a second position the element is substantially parallel to Z and the first end is disposed in a plane corresponding to an electric field maximum within ±30%.

Abstract: A radiofrequency filter exhibiting at least one resonant mode comprises: at least one cavity at least partially closed using conductive walls, having a cylindrical outer surface defined by a directing curve described by a generatrix and having a point of symmetry, an axis passing through a point of symmetry and parallel to the generatrix being a longitudinal axis of the cavity. At least one dielectric element is arranged in the cavity and comprises: a first portion having a thickness according to the longitudinal axis and a section according to a plane perpendicular to the longitudinal axis whose vertices are distributed according to a polygon, at least two vertices being short-circuited between them by the conductive walls of the cavity, via an electrical or radiofrequency contact between the vertices and walls, at least one pyramidal portion comprising an apex and a base coinciding with an extreme section of the first portion.