1.First of all, to understand the purpose of the use of shielded box: First, limit the radiant electromagnetic energy within the device out of a certain area; second is to prevent external radiant electromagnetic energy into a certain area.
2. Shielding effectiveness of shielding box: When the simulated interference source is placed outside the shielding box, the ratio of electric field strength, magnetic field strength or power at a certain point before and after the shielding box is placed is taken as the logarithm (lgp1/p2), expressed in dB. .
3, shielding box test equipment: network analyzer (signal generator + spectrum analyzer), dipole antenna, horn antenna, shielded box.
4, the specific role and scope of application of shielding box:
For manufacturers of wireless communication products, the inability of the products to be available on the market or the rapid sale will result in the loss of large amounts of output value and profits, which will directly affect the follow-up business and market share expansion.
The RF test process is usually the most complicated and most influential process in the production of wireless communication equipment such as mobile phones, and is usually the bottleneck of the production line. RF test stations are usually composed of test instruments, shielding boxes, test software, and other parts, and usually can be divided into calibration test, comprehensive test, antenna test and so on. Due to capacity requirements, the RF test process is usually run in parallel by multiple identical test stations. The passing rate of one or some test stations is low; if the output is reduced, it will lead to bottleneck in the production line and a sharp increase in production costs. The reason can be roughly divided into: Product design or material reason, test problem (mistake) (Testing problems), radio frequency interference and other environmental factors, testing uncertainty.
5, the classification of shielding box
The shielding box can be manufactured into manual, pneumatic, fully automatic and other different working modes according to different testing requirements. Fully automatic shielding box is through the international standard RS232 interface according to the communication instructions to test the shielding box to complete the test process, generally for small RF modules, large-scale production line production when used to improve production efficiency. Manually shielded boxes, which are generally small in size and easy to operate, are the most commonly used ones on small-scale communication equipment such as mobile phones and other production lines. There are also some parts that are too large in size and use manual door-to-door access due to the inconvenience of pneumatic operation. Pneumatic shielded boxes are generally large in size and are used in production tests to improve test efficiency and reduce operator fatigue.