Characteristics of the Magnetic Attenuator at UHF

Certain ferromagnetic materials such as ferrites have considerable loss at frequencies in excess of 30 mc. This loss can be controlled by producing a magnetic field in the material by external means, such as an electromagnet. This principle is used in the small electrically controlled variable attenuator for coaxial lines which is described. The performance of the attenuator at ultra-high frequencies is given for a specific attenuator using a number of suitable materials. The design and applications of the attenuator are also discussed.