BANDPASS MICROWAVE FILTER TUNABLE BY ROTATION OF A DIELECTRIC ELEMENT

摘要

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%.

主权项

1. A bandpass filter for microwave-frequency wave, frequency tunable, comprising at least one resonator, each resonator comprising:
a cavity having a conducting wall substantially cylindrical in relation to an axis Z having a height H, a position z along the axis Z being labelled by an abscissa z lying between 0 and H, and being at least partially closed at both ends and, and at least one dielectric element disposed inside the cavity; said resonator resonating according to a mode for which two perpendicular polarizations respectively have distributions of the electromagnetic field in the cavity that are deduced from one another by a rotation of 90°; said mode having in said cavity N maxima and N+1 minima of electric field which are situated substantially in a plane perpendicular to the axis Z, the two ends of the cylinder respectively at the abscissae z=0 and z=H corresponding to electric field minima, successive minima and maxima being spaced apart by a separation distance H/2N; further comprising: means of rotation adapted for setting said element into rotation in relation to an axis R substantially perpendicular to the axis Z, between at least a first and a second position; said element comprising at least one first end such that: in a first position the said element is disposed substantially in a plane perpendicular to the axis Z and the centre of said first end is disposed at a height in the cavity corresponding substantially to a minimum of the electric field, in a second position said element is substantially parallel to Z and said first end is disposed in a plane corresponding to an electric field maximum to within ±30%.