TEMPERATURE COMPENSATION TYPE MAGNETOSTATIC SURFACE WAVE FILTER

摘要

PURPOSE: To prevent a center frequency from being increased due to the rise of a temperature by forming the temperature characteristic in the magnetic field of a permanent magnet to be opposite in the polarity to the temperature characteristic of the strength of the magnetization of a ferromagnetic single crystal thin film. ;CONSTITUTION: A metallic thin film pattern 3, an input side strip transducer 4, an output strip transducer 5 are formed on a dielectric board 1. Moreover, single crystal plate 2 with a ferromagnetic single crystal thin film formed to its one side is fitted onto the board 1. A samarium erbium cobalt magnet 7 for applying a DC external magnetic field is fitted to the inside of both legs of a yoke 10 whose cross section is U-shaped. The temperature characteristic in a straight polarity is realized by replacing 40mol% of the samarium of the magnet 7 with erbium. Since the quantity of the magnetization of the ferromagnetic single crystal thin film is decreased attending on the rise of temperature, the fluctuation in the center frequency of the filter is suppressed by constituting the filter so that the temperature characteristic in the straight polarity is provided on the DC external magnetic field.;COPYRIGHT: (C)1993,JPO&Japio