Shielding is used for two purposes:
One is to limit the radiation electromagnetic energy inside the equipment to cross a certain area;
The second is to prevent the external radiation electromagnetic energy from entering a certain area.
Shielding effectiveness of shielding box:
When the analog interference source is placed outside the shielding box, the ratio of electric field strength, magnetic field strength or power of a point in the space before and after the shielding box is taken as logarithm (lgp1 / P2), expressed in dB.
The shielding box test equipment includes:
Network analyzer (signal generator + spectrum analyzer), dipole antenna, horn antenna, shielding box.
Classification of shielding box (RF isolation box):
It can be manufactured into manual, pneumatic, automatic and other different working modes according to different testing requirements.
1. Manual shielding box, generally small in size and convenient in operation, is currently used in small communication equipment such as mobile phones and other production lines. In addition, some of them are too large, and manual door watching is also adopted for those inconvenient in pneumatic operation
2. In order to improve the test efficiency and reduce the operator's fatigue, the pneumatic shielding box is usually large in size
3. The full-automatic shielding box controls the testing shielding box according to the communication instructions through the standard RS232 interface to complete the whole testing process. Generally, it is used for small RF modules and large-scale production line to improve the production efficiency
Usage of shielding box
Specific functions and application scope of signal shielding box (RF signal shielding box):
For wireless communication product manufacturers, the loss of a large number of output value and profits is caused by the failure of products to be put on the market in time or the rapid increase of quantity. Directly affect the subsequent business and market share expansion.
RF testing technology is usually a complex and influential process in the production line of wireless communication equipment such as mobile phones, which is also the bottleneck of the production line. RF test station is usually composed of test instrument, shielding box, test software and so on. It can be divided into calibration test, comprehensive test, antenna test and so on. Due to the requirement of production capacity, the RF test process is usually run in parallel by several same test stations. The passing rate of one or some test stations is low; the production line bottleneck and production cost will increase sharply if the output is reduced. The reasons can be roughly divided into: product design or material reasons, test problems (false test problems), radio-frequency interference and other environmental factors, and test uncertainty.
Electromagnetic interference / EMI is a problem that must be faced and overcome in the whole electronic field at present. Generally, in wireless communication products, such as mobile phones, wireless network cards, wireless routers, wireless headphones, Bluetooth headphones, Wi Fi, WiMAX, data cards, walkie talkies, RFID and other wireless communication equipment and wireless communication modules, during the board test and final test, RF is used Test the shielding box / RF shield box to improve the test environment.
1、 Shielding box function
– isolation of external base station signals
– isolate interference from adjacent test stations
– reduce the impact of people
– save handling time
– integration of multiple test processes to simplify the process
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