Pass band filter with dielectric resonators - uses ferrimagnetic elements subjected to external magnetic field to modify resonant frequency

摘要

A section of waveguide (1) is closed with plates through which connectors protrude to support antenna dipoles. Resonant assemblies are mounted internally on a large side of the waveguide. These assemblies are aligned and evenly spaced. Each assembly comprises a support ring (S1) of a low permitting dielectric material. This supports a dielectric resonator disc (11) on which a spacer (12) is mounted. This has low loss and low dielectric constant and is able to shift the operating upwards for the filter. A ferrimagnetic element (13) is mounted on the spacer. The resonator assemblies are subjected to magnetic fields which act on the magnetic elements to tune them. This is effected by a current source (4) driving a winding (52) on a soft iron core (5). Screws (50,51) allow the gap between the poles to be adjusted.