| 摘要 |
PROBLEM TO BE SOLVED: To reduce the weight of an element and to lower the price by using a sintered ferrite for the core of an electromagnet so as to accelerate the resonance-response speed of a band-pass filter. SOLUTION: A gap is provided at a part of a ferrite core 31 and a thin permalloy plate 32 is stuck to both ends of it. In addition, a YIG crystal 34 is arranged in this gap to make a control current flow through an energizing coil 33. Thus, a magnetic flux is generated in the core 31 and a magnetic field is generated in the gap. By sticking the plate 32 to both ends of the gap, performance sufficient for resonating with a high frequency is obtained. There is a nearly proportional relation between the intensity of a magnetic field to be applied and a magnetic resonance frequency, consequently, the magnetic resonance frequency increases in accordance with the magnitude of the coil current. On the other hand, the magnetic saturation at the gap end part is prevented by sticking a thin plate such as permalloy of high magnetic saturation to an end part. |
