## 3 Test Results  
### Analysis of Vertical/Horizontal Wave Measurement Results of Eight Specimens  
As shown in Figure 4, a maximum 40 dB difference occurred in the 0.1 MHz-300 MHz band compared to the blue line, indicating that the shielding efficiency was high for the vertical (V) wave in the slit direction. That is, since the long slits showed different shielding efficiencies for horizontal and vertical waves, countermeasures for the slit direction were required to increase total shielding efficiency. The consistent slope from 0.01 MHz to 10 MHz in the shielding standard was attributed to being adjusted to a reasonable reference value, as it was difficult to shield a magnetic field in this range. In addition, since the energy value of the electromagnetic wave was proportional to the Planck constant and frequency, the energy in the low-frequency region was low, so it was judged to be safe despite having low shielding efficiency. As shown in Figure 5, as a result of placing the conductive tape between the amorphous soft magnetic sheets overlapped with a width of 20 mm to increase the shielding efficiency at the slit, the overall shielding efficiency increased by more than 10 dB in the horizontal and vertical directions. However, there was still a difference in shielding efficiency in the horizontal and vertical directions in the 0.1 MHz-300 MHz band. Figure 3: Experimental instruments. As shown in Figure 6, as a result of increasing the width of the overlapping portion of the conductive tape from 20 mm to 50 mm, the overall shielding efficiency increased by more than 10 dB, and the difference between the horizontal and vertical shielding efficiency in the 1 MHz-300 MHz band was reduced. Figure 4: Shielding effectiveness of specimen #1(W = 0). Figure 5: Shielding effectiveness of specimen #2 (W = 20). As shown in Figure 7, the overall shielding efficiency was increased by more than 10 dB by increasing the width of the overlapping sections to 100 mm, and the deviation in the horizontal and vertical directions was reduced in the 0.1 MHz-300 MHz band. In Figure 8, the shielding efficiency was dramatically increased by attaching an additional conductive tape to the overlapping area. There was a section in which a reversal phenomenon was noted in the horizontal and vertical shielding efficiencies, which showed a significant difference in the 0.1 MHz-300 MHz band, but the overall efficiency values were consistent. Figure 6: Shielding effectiveness of specimen #3 (W = 50). Figure 7: Shielding effectiveness of specimen #4 (W = 100). In Figure 9, the overall shielding efficiency was improved as the overlapping area increased by attaching additional conductive tape in an alternating pattern. The reason that the horizontal shielding efficiency was lower than that of the specimen overlapped by 50 mm in the 0.1 MHz-10 MHz band may have been due to manufacturing errors. However, in the other parts, the shielding efficiency was higher when the overlapping specimen was 100 mm, as compared to 50 mm. Figure 8: Shielding effectiveness of specimen #5 (W1 = 50, W2 = 20). Figure 9: Shielding effectiveness of specimen #6 (W1 = 100, W2 = 20). As shown in Figure 10, specimen #7 met the shielding efficiency criteria in all bands. Since this specimen was manufactured with a sandwiched structure, the efficiency increased, as there were twice as many soft magnetic layers as other materials. The reason that gaps still occurred in the horizontal and vertical directions in the 0.1 MHz-300 MHz band was attributed to the amorphous soft magnetic layers being arranged in parallel. The reason that the shielding efficiency increased consistently, up to 100 MHz, in most specimens and then decreased sharply was attributed to the frequency dependence of magnetic permeability. Permeability is the frequency sensitivity of electron spin; magnetic permeability is dependent on the frequency, and frequency dependence is different depending on soft magnetic materials.