Should dead copper be removed in PCB design?
Some people say it should be removed for the following reasons: 1. EMI problems will be caused. 2, enhance the ability to disrupt. 3. Dead copper is useless.
Some people say it should be kept, the reasons are probably: 1. Sometimes large blank space does not look good. 2, increase the mechanical properties of the board, to avoid the phenomenon of uneven bending.
First, we do not want to die copper (island), because the island here to form an antenna effect, if the radiation intensity around the line is large, will enhance the radiation intensity around; And will form the antenna reception effect, will introduce electromagnetic interference to the surrounding wiring.
Second, we can delete some small islands. If we want to keep the copper coating, the island should be well connected to GND through the ground hole to form a shield.
Third, high-frequency, wiring of distributed capacitance on the printed circuit board will work, when the length is more than 1/20 of the noise frequency corresponding wavelength, can produce the antenna effect, the noise will launch out through wiring, if there are bad grounding copper clad in the PCB, copper clad became the tool of transmission noise, therefore, in the high frequency circuit, do not think, The ground somewhere connected with the ground, this is the “ground”, must be less than λ/20 spacing, in the wiring hole, and the floor of the multilayer board “good grounding”. If the copper coating is properly treated, the copper coating not only increases the current, but also plays a dual role in shielding interference.
Fourth, by drilling the ground hole, keep the copper covering of the island, not only can play a role in shielding interference, but also can prevent PCB deformation.