Band Stop Filter Design Based On The Ferromagnetic Thin Film Magnetic Tune

The frequency range of 10 to 100 GHz is particularly interesting for military, communications and security applications. For example, there are obvious needs to see through fog, clouds, and smoke, but this cannot be done in visible light or infrared radiation. So it's important to study the circuits and devices that operate at high frequencies. With the development of the technique, the receving system has been integrated to a single chip except the filter. The filter has become the biggest parts in receving system. It's becoming a necessarily and important task to reduce the bulk of filter. This paper will study a magnetic tunable filter which is compatible to the integrated IC. The magnetic tunable band-stop filter, which the stop band can be changed in a wide range of frequency with the variable magnetic field, works in the theory of ferromagnetic resonance. Most current devices are based on a low-magnetization ferromagnetic insulator. Our work, in contrast, uses an approach in which the high magnetization, metallic ferromagnets are active elements in these filters. This high magnetization allows the high-frequency operation. We use the FeCoB to produce a magnetic band-stop tunable filter. The FeCoB film has a high magnetization, and then it can allow us to operate the filter at a high frequency using a low field.In this paper, three aspect of the magnetic band-stop tunable filter was discussed. First, the design technic of the filter was studied. We had designed the circuit of filter and mask in preparation to the grown film. Secondly, we had constructed magnetic grown by magnetron sputtering, a technique commonly used in industry. The sputtering technique has a second advantage that can produce the thicker films than other technique. Finally, the drivers was devised to provide the tunable magnetic field for the filter. The driver provides the compensation for temperature drift, the high precision of the tunable current and the widely adjusted range of current for the filters.In all, this paper presents a tunable band-stop magnetic filters and a drivers. We obtained the knowledge of the film devices and the rules of design magnetic devices through the study of this filter.