Abstract: A layered microstrip device is described, in which at least two layers of different high internal field/high resonance frequency materials serve as the active elements of the device. The device is designed to filter ranges of high frequency electromagnetic waves, and is on a small scale to enable integration with high frequency electronics. The ranges of frequencies to be filtered depend on the active elements and device geometry selected for the device. The tradeoffs regarding active material and device geometry choices are explored in detail. The ranges of frequencies to be filtered can be modified in real time with the application of an external magnetic field. A variety of the devices were fabricated, and a number of experimental and theoretical studies were carried out.