Microwave resonators and microwave filters incorporating microwave resonators

摘要

A magnetically tunable microwave resonator comprises a resonator block (11) made from a ferrimagnetic material. The effective permeability, and so the resonant frequency, of the resonator block can be altered by subjecting the block to a magnetic field bias which could be an external continuous magnetic field bias obtained from a coil 20, polo pieces (30, 31 Fig 3) or C-shaped ferrite cones (51, 51' Fig 5) or an internal, latched magnetic field bias obtained by a longitudinal or transverse current carrying wire (40, Fig 4). The inner and outer side surfaces of the block 11 are provided with metal layers 13, 14 eg silver, copper or aluminium. In a modification (Fig 6b) the resonator block may be of two axial sections (62, 63) one being of ferrimagnetic material and the other being of ceramic material. In a further arrangement two coaxial cylinders (60, 61, Fig 6a) may be used having the inner one of ferrimagnetic material and the other one of a high dielectric material. Magnetically tunable microwave filters are described (Fig 7a-7d) including a plurality of the magnetically tunable microwave resonators. IMAGE