A High-Q Ferrite-Tuned Cavity

A model for ferrite-loaded transversely biased coaxial resonators

“…Although the method is not particularly accurate, building up from the basics, it seems to capture the general tendency of tuning characteristics of the resonator, which is in agreement with previous findings [2]. The calculations can therefore be regarded as a valid approximation.…”

“…In some practical applications, the tuning range requirements are not as challenging and can be met by loading only a fraction of the cavity volume with a ferrite sample [2]. In such cases, for an expression that is equivalent to Equation 5 to be derived, the reflection at the interface of the ferrite-loaded line and the air-filled line needs to be taken into account.…”

“…Ferrite-loaded, magnetically tuneable coaxial cavity resonators operating in the radio frequency (RF) range are commonly used in particle accelerators [1][2][3]. The frequency of resonance in such cavities can be tuned by changing the DC magnetic field applied onto the ferrite elements.…”

“…This is possible due to the bias-dependent magnetic behaviour of ferrite materials. With the introduction of the transverse bias configuration [2] where the bias field is parallel to the axis of the cavity, it was shown that the quality factors (Q) of these resonators could approach those of unloaded cavities of the same geometry [4]. Despite their favourable features and utilization in practice, no simple way of calculating the resonance frequencies given the geometry and material properties seems to exist in former literature.…”

Ferrite Characterization for the Design of an Accelerating Cavity With Perpendicular Biasing

“…It was shown by Earley that a magnetic bias field which is perpendicular to the RF magnetic field can lead to a much higher magnetic Q of the ferrite in comparison to parallel biasing [1]. Prototypes of such cavities were built and tested e.g.…”