Mitigate the Interference: Nonlinear Frequency Selective Ferrite Devices

The linear "small-signal" properties of ferrites gave rise to several well-known microwave devices [1], [2], such as circulators, isolators, phase shifters, tunable oscillators, and tunable filters, that have had a significant impact on microwave systems following their first synthesis by Snoek [3], [4] in 1945. However, ferrites also show useful nonlinear "large-signal" properties that have been applied in power-limiter and power-enhancer devices. While these devices have not seen widespread application, their unique frequency-selective signal attenuation properties offer potential solutions to current and anticipated radiofrequency (RF) interference problems resulting from ever-increasing signal density and demands on scarce RF bandwidth.