The higher the shielding effectiveness

13 low-frequency magnetic field shielding effectiveness of Rs H0 H1 R0 RS = R0 = shield air reluctance reluctance SE = H0 / H1 = (RS + R0) / RS = 1 + R0/RS 14 Conclusion reluctance shield smaller, the higher the shielding effectiveness. shield reluctance smaller, the higher the shielding effectiveness.'s reluctance to reduce the shield, it should be: reducing the shield's reluctance, it should be: the shield as small as possible, so you can make the magnetic circuit as short as possible, from the shield as small as possible, so you can make the magnetic circuit as short as possible, to achieve the purpose of reducing the reluctance to increase the cross-sectional area of 15 magnetic permeability as high as possible using the low-frequency magnetic field shielding materials.
Communication passive shielding an object sensitive equipment to prevent external interference source to its sensitive equipment, interference shielding sensitive equipment 4 object concept of shielding effectiveness of shielding effectiveness of shielding when there is no room for a location in the field with a shield when the location of the ratio of field strength, intensity and shielded position when the field strength ratio, which characterized the shield on the electromagnetic wave attenuation. a shield for the attenuation of electromagnetic waves if the shielding effectiveness of the magnetic field used in the calculations, is called magnetic shielding effectiveness; be used in the calculations of the magnetic field, is called the magnetic field shielding effectiveness;The cover frequency bands of cell phone jammer are complete. if calculated using the electric field, if calculated using the electric field is known as the electric field shielding effectiveness: SE = 20 lg (E1 / E2) dB 5 Second, the active principle of the electrostatic field shielding electrostatic field shielding principles to achieve an effective shield, the shield must be grounded electrostatic field to achieve an effective shield, the shield must be grounded. 6 principles of passive shielding the electrostatic field theory of the electric field shielding passive shielding, move shield, the shield should be grounded, to keep the ground potential, ground potential, to achieve effective shielding 7 passive shield shield shield grounding of the electric field shielding effectiveness because of the linear system, because the linear system, the induced voltage proportional to the interference field strength, so Vi SE = 20 lg Vip 11The shielding ranges of    cell phone jammer are optional. Third, the magnetic shielding magnetic shielding is used to isolate the magnetic field coupling measures magnetic shielding is used to isolate the magnetic coupling of the magnetic field measures shield divided into high-frequency and low frequency magnetic field shielding Magnetically shielded high frequency magnetic field shielding using a good conductor of high conductivity, good conductor of electricity rate, the eddy current induced on the conductor in the opposite direction of the magnetic field generated by offset magnetic field interference.'s magnetic field to offset the interference magnetic field. Induction Cooker works frequency? Induction operating frequency?The    cell phone jammer        works automatically. 20K-27KHz frequency: high frequency: 12 low-frequency magnetic field relative to the concept of shielding H0 R0 Rs H1 low-frequency magnetic field shielding materials with high permeability, low-frequency magnetic field shielding materials with high permeability, high conductivity magnetic materials to provide a low reluctance path magnetic field lines, magnetic materials to provide a low reluctance path magnetic field lines, so that the magnetic field shielding the body enclosed in the sky isolation. field enclosed in a shielded body sky isolation. So it needs no people to maintain the    cell phone jammer       .