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WiFi antenna requirements for PCB layout and structure
Source:Original | Author:C&T RF Antennas Inc | Publish time: 2018-10-26 | 2184 Views | Share:

3. Microstrip line from WiFi module to antenna matching circuit

The signal transmission line from the WiFi module to the antenna matching circuit is a microstrip line with a 50-ohm characteristic impedance. To avoid losses on the microstrip line, the module should be as close as possible to the antenna. The microstrip line must be sized according to the specific PCB. Crossed lines are not allowed to pass between the microstrip line and the ground.

4. Some other questions

Grounding: Good RF grounding is undoubtedly very important for the wireless performance of mobile phones. The following design principles must be followed:

Try to make the ground in the outer layer intact and not be broken (the part inside the non-shield), which is especially important for the area near the antenna. The antenna current must be isolated from the noise current. If the grounded area near the antenna is broken into incomplete, a fill plane must be created in the relevant area below it and stitched with the ground via to make it a complete ground. The traces in this area must ensure that the antenna current flows only through the surface plane and that the noise current must flow into the complete ground plane.

When using a pre-production antenna, it is important to note that its characteristics depend on the ground plane to which it is connected. Only when the size and shape of the ground plane are consistent with the manufacturer's evaluation board can the specifications specified by the manufacturer be met. In other cases, the user needs to measure the impedance of the pre-produced antenna under actual application conditions and match to the desired characteristic impedance.

5. Problems with the use of metal components in the equipment casing

Do not use metal-coated spray or plating on the surface of the casing. Metal plating cannot achieve reliable grounding, which will have a great impact on antenna performance.

Do not use metal decorations near the antenna.

6. Use of pure metal structural parts