Dielectric resonance in nickel ferrite for K and Ka‐band filters
Author(s) -
Popov Maksym A.,
Zavislyak Igor V.,
Murthy D. V. B.,
Srinivasan Gopalan
Publication year - 2014
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.28195
Subject(s) - materials science , dielectric , microwave , ferromagnetic resonance , ferrite (magnet) , insertion loss , band stop filter , frequency band , resonance (particle physics) , dielectric loss , filter (signal processing) , optoelectronics , low pass filter , optics , nuclear magnetic resonance , magnetic field , electrical engineering , telecommunications , physics , bandwidth (computing) , engineering , atomic physics , magnetization , quantum mechanics , composite material
ABSTRACT The nature of dielectric resonance and its utility for a magnetic field tunable band‐pass filter have been studied in a polycrystalline disk of nickel ferrite. The lowest order dielectric resonance manifests as two modes corresponding to clockwise and counter‐clockwise polarization of the microwave fields. Under the influence of a static magnetic field perpendicular to the disk plane, one of the modes show a decrease in frequency whereas the other shows an increase in frequency. With increasing H, the frequency separation increases. Band‐pass filters for operation at 19, 30, and 35 GHz have been designed and characterized. The filter central frequency has been controlled with proper choice of disk dimensions. The filter frequency is tuned with H, by 2–7%. As the filter frequency is well above the ferromagnetic resonance frequency expected for the static magnetic fields, the overall losses are small with the insertion loss ranging from 2 to 5 dB. Theoretical estimates of H‐tuning of dielectric resonance and pass‐band are much higher than measured values, indicative of potential for further improvement in filter performance. The ferrite filters are of importance for use in the K and Ka‐band communication devices. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:814–818, 2014