EVALUATING DEVICE FOR CAPABILITY OF EXCLUDING INCIDENT INTERFERENCE

摘要

PURPOSE:To obtain an evaluating device for a capability of excluding incident interference which enables the proper maintenance of a field strength inside parallel conductors in the range of desired frequencies and has compact sizes, by using a ferrite wave absorber. CONSTITUTION:A radio-wave dark box 20 is formed of a metal case 19 and is fitted with a thin ferrite wave absorber 30 on the whole inside surface thereof. A strip line is arranged with the lower conductor 1 thereof laid on an insulating retainer so that the central axis in the longitudinal direction is in accord with one diagonal line of the floor surface 20a of the dark box 20, and the distance between the upper conductor 2 of the strip line and the ceiling of the dark box 20 is set so that it is larger than the distance between the parallel conductors 1 and 2 of the strip line. Such a constitution produces the result of curbing the effect on the field strength inside the line by the re-incidence of electromagnetic waves having frequencies higher than that of the strip line acting as an antenna, etc., and enables the proper maintenance of the field strength inside the parallel conductors within the desired range of frequencies.