Ferrite-Tunable Filter for Use in S Band

Using recently developed low magnetization ferrite materials, it is possible to extend the application of ferromagnetic resonance absorption down through S band. An electronically tunable image rejection filter designed to operate with a 2 to 4 kmc receiver has been constructed in coaxial transmission line. Image suppression considerably greater than 50 db with signal attenuation only 1.5 db is attained for an intermediate frequency of 500 mc.