Tunability of microstrip ferrite resonator in the partially magnetized state

A theoretical analysis is presented for a microstrip ferrite resonator of microwave frequency /spl nu//sub r/ that is tunable by varying the state of magnetization. Measurements at 8 GHz indicate a 5% tunability range for a magnetic field H <50 Oe. Calculations of /spl nu//sub r/ as a function of H are fitted closely to data. Computed performance estimates of a superconducting resonator with an ideal magnetic structure project a remanent-state tunability limit of 25% and an X-band figure of merit of 7000 for a Q factor of 10/sup 4/.