The radius of covering range of cell phone jammer

With the formula can be expressed as: SE = A + R + B (see Figure 1). Absorption loss A = 131. 43t consumption, R = 168 + 101g (= 201g (1 - e - 2t rr rr for its size and has higher conductivity or lower permeability of the material, the greater the reflection loss for magnetic waves and near-field source the electric field wave near-field sources have the same situation. B is due to multiple reflection transmission loss through the internal wave attenuation after he hit the other side of the shield and on the side of the reflection and transmission, the reflected wave and multiple reflections, the rapid decay of energy for thicker shield (requires A> 10dB), the electric field for the near zone electric field or plane wave electric field can be the size of B is not considered.More than 200m away from the base station, the radius of covering range of cell phone jammer is 20-50m. In summary, the high absorption of low reflectivity electromagnetic shielding materials to meet the accuracy requirements are the focus of research, namely to find a product meet the ratio of large and small rrrr material reality, when the SE is less than 30dB for the poor; 60 ~ 90dB is good, can be used for aerospace and the shield of military equipment; 90dB or more for the gifted, for demanding high precision and high sensitivity products, according to practical needs, for most electronic products, shielding material, in the frequency range 30 to 1000, the SE of at least 35dB above, a square that is an effective shield. frr (dB); R is the wave of a single reflection loss for the material relative to copper, the magnetic permeability; f) (dB) (far plane wave); multiple reflection loss B tt) (dB). The range can be enlarged after adding the directional antenna of     cell phone jammer   . Among them, the conductivity of the material relative to copper; f is the frequency of electromagnetic waves; t is material thickness; the skin depth = (! Of) - 1 2. Specifically, the absorption loss A is the conductor of the electric dipole or magnetic dipole and electromagnetic effects. Size and frequency only, the shield thickness, conductivity and magnetic permeability for, f, rt, r 1 mechanism of two electromagnetic shielding, anti-touch screen technology alarm system transmission and distribution lines is used to prevent truck crane, walking classes and various types of crane jib cranes and dump trucks and other large mobile equipment, overhead lines reach the wireless alarm device. Therefore, it becomes extremely urgent to install    cell phone jammer system in prisons.The alarm on looming power lines have early warning of dangerous situations, the transmitter and the receiver is divided into two parts [2]. Transmitter is located on the operating arm, the sensor, amplifier, filter, filter rectifier circuit, starting and wireless transmitter circuit, 50Hz signal in the transmitter detects the larger A value greater. You can use a larger permeability material such as nickel-iron-molybdenum magnetic alloy superconductors and other materials or methods such as by stacking layers of materials to increase the absorption loss. R is the reflection loss due to space intrinsic impedance and shield impedance mismatch between the cause, is the conductor of the charged particles (free electrons or holes) with the result of the interaction of electromagnetic fields. Normally, the   china cell phone jammer system installed in the prison will be installed at a high position or a relatively hidden position so that it wouldn’t be easy to be found. Author: Xiabing Sen (1981 -), male, Fujian Fuqing, North China Electric Power University, School of Electrical and Electronic Engineering, Communication and Information System 05 Master.