Cell phone jammer strains rapidly

The higher the frequency of electromagnetic waves are shielded, the greater the absorption loss. 23 far-field reflection loss is calculated: the far field: 377 R 20 lg Z0 4 Z1 near-field: near-field: depending on the source characteristics jω Z1 to shield characteristic impedance: Z1 = σ + jωε characteristic impedance of the shield: Z1 = 3.69 × 10-7 √ fr / σr σ the characteristic impedance of the same material change with frequency and wave impedance for return loss, the higher the wave impedance, return loss and wave impedance, the higher the impedance, the reflection loss more 24 The Vs   cell phone jammer strains rapidly.The concept of a large acoustic impedance impedance definition: the definition of impedance: impedance values: the value of impedance: near-field: near-field: the electric field of the wave impedance is greater than the intrinsic impedance of medium wave impedance of the magnetic field is less than the medium the intrinsic impedance Z 0 = E / H Z0 e λ0 1 = = 60 2πfε0 rrr = 2πf0 r = 2369 λ0 far field: the medium is equal to the intrinsic impedance of the far field: Z0 m wave impedance changes: changes in impedance: nearly field: according to the nature of radiation, near-field: according to the nature of radiation, far-field changes with distance: the far field: Within seconds after turning the    cell phone jammer        switch on, it shields all kinds of cell phone signals.the impedance remains constant near-field and far field boundaries: near-field and far-field boundaries: λ / 2π 3 λ0 25 impedance characteristics of wave impedance E / H 377 field-based E α 1 / r3 H α 1 / r2 plane wave E α 1 / r H α 1 / r field-based H α 1 / r3 E α 1 / r2 λ / 2π to the observation point far-field distance r 26 Conclusion: the wave impedance of the electromagnetic far field: the electromagnetic wave impedance of 377.
The difficulties of low-frequency magnetic field of high frequency magnetic conductive material: highly conductive materials to absorb reducing the absorption skin depth) (reduced skin depth) the high reflection loss of small conductive materials to absorb losses small high-magnetic materials: lead high-magnetic materials: low reluctance path) (low reluctance path) shielding effectiveness of magnetic shielding material with low 16 frequency r 103 15 nickel permalloy steel cold-rolled steel 5 permeability changes with field strength magnetic flux density B = B / H saturation maximum permeability initial permeability of the magnetic field strength H 18 high-frequency magnetic field shielding permeability materials: high-permeability materials: saturated low permeability materials: low-permeability materials: low-permeability screen effect is not enough material high permeability material 19 So    cell phone jammer doesn’t need to be maintained by human.Fourth, the principle of electromagnetic shielding of electromagnetic shielding is the use of high frequency electromagnetic energy shield to prevent propagation of electromagnetic shielding in space reflecting the principle of multiple reflection absorption loss loss loss of 20 solid materials, the calculation of shielding effectiveness of shielding materials, the thicker the incident wave, the greater the absorption loss, the thicker the shielding material, the greater the absorption loss, a trend to increase the thickness of each skin depth, the absorption loss by about a skin depth, the absorption loss increase of about 9dB;; shielding material, the higher the permeability, the greater the absorption loss; shielding materials, the higher the permeability, the greater the absorption loss; shielding material The Vs    cell phone jammer        could work in all kinds of environment.The higher the conductivity, the greater the absorption loss; the higher conductivity of shielding material, the greater the absorption loss; masked the higher the frequency of electromagnetic waves, the greater the absorption loss.