Tech Note: Why Use A YIG-Tuned Filter?

YIG filters utilize the same high-Q microwave resonance phenomenon as other YIG-based products but in a slightly different way. In YIG-based products, the resonant frequency exhibited by the YIG material is determined by an applied magnetic field. By placing a YIG sphere inside a magnetic field created by an electromagnet, for example, the resonant frequency can be changed by adjusting the current through the electromagnet. The resonant frequency of YIG-based oscillators and filters can vary over a wide range with a high degree of linearity by simply controlling the magnet drive current.