shield box is a kind of shielding body with various shapes made of conductive or magnetic conducting materials, which limits the electromagnetic capacity to a certain space and is used to suppress radiation interference. It also deals with the conduction and radiation, so as to provide a non-interference test environment for the tested wireless communication equipment.
　　Shielding effect and classification
　　Shielding effect:
　　One is to limit the radiation electromagnetic energy inside the equipment to exceed a certain area, that is, to absorb the internal interference signal;
　　The second is to prevent the external radiation electromagnetic energy from entering a certain area, that is, to shield the external interference signal Shielding concept: refers to the ratio of electric field strength, magnetic field strength or power of a point in the space before and after the shielding box is placed, and then takes the logarithm (lgp1 / P2), which is expressed in dB
　　Detection equipment: network analysis, signal generator, spectrum analyzer, dipole antenna, horn antenna, shielding box
　　Classification: it can be divided into manual shielding box, pneumatic shielding box and full-automatic shielding box according to different test requirements
　　1. The manual shielding box is easy to operate. Test mobile phones, laptops, pads and other devices have corresponding size devices. It is suitable for R & D, testing, certification and other institutions.
　　2. Pneumatic shielding box is mostly used in production test, which improves test efficiency and reduces operator's fatigue. Test mobile phones, laptops, pads and other devices have corresponding size devices.
　　3. The full-automatic shielding box completes the whole test process by controlling the testing shielding box according to the communication instructions through the international standard RS-232 interface. Generally, it is used for small RF modules and large-scale production lines to improve the production efficiency.