Perpendicular biased ferrite-tuned cavities

A new slip stacking RF system for a twofold power upgrade of Fermilab׳s Accelerator Complex

“…The DC bias field which is varied to change the effective permeability of the garnet and thus the cavity frequency, is perpendicular to the RF magnetic field. The perpendicular bias approach has been pursued with success [18][19] [20][21] [22], but traditionally and most often, parallel biased ferrites such as NiZn have been used for cavity tuning. Some examples of this are in the FNAL Booster [23], Main Ring [24][25], the CERN PS [26] and the Brookhaven AGS [27].…”

A Study of Rapid Cavity Tuning.

“…On the other hand, if one changes the frequency to keep the circumference harmonic number h constant m~= 2nh = cot2stant, (5] ( 6) meaning that the frequency will change linearly with time.…”

“…This, according to (24), requires a frequency difference of~2 -fl=l/r. For frequency tuning, according to (6), it is proportional to AZ However, problems remain. "The power handling capability of the device is the same.…”

A low-loss, continuously tunable microwave notch filter

“…In this work, the shortened coaxial resonators of coaxial combline filters are filled with ferrite inserts in order to obtain the tuning effect. Although such ferrite-tuned shortened coaxial cavities have been used in particle accelerators before [22, 23], to the best of the authors’ knowledge, they have not been utilized in tunable filter design. It is shown in this work that the mentioned tuning technique can be exploited to design and realize continuously tunable filters that deliver desirable characteristics in terms of both tunability and loss levels.…”