High frequency PCB layout
The less alternating leads of the pins between the layers of high frequency circuits, the better.


This means that the less Via is used in connection, the better. A Via can bring about a distribution capacitance of about 0.5pF, reducing the number of Via can significantly increase the speed and reduce the possibility of data error.


The shorter the lead between the pins of high-frequency circuits is, the better it is.


The radiation intensity of the signal is directly proportional to the routing length of the signal line. The longer the high-frequency signal lead is, the more easily it can be coupled to its components. Therefore, for high frequency signal lines such as signal clock, crystal oscillator, DDR data, LVDS, USB and HDMI, the shorter the routing length is required, the better.


The less bend between the pins of high-frequency electronic devices, the better.


High frequency electrical wiring leads had better use full straight line. If a break over is required, a 45 degree broken line or arc break can be used. This requirement is only used to improve the bonding strength of copper foil in low-frequency circuits, while in high-frequency circuits, meeting this requirement can reduce the external emission and coupling of high-frequency signals.


Pay attention to the &quot;crosstalk&quot; introduced by the signal line parallel to close distance.


For high frequency circuit wiring, attention should be paid to the &quot;crosstalk&quot; introduced by the signal line parallel in a close distance. Crosstalk refers to the coupling phenomenon between signal lines without direct connection. Since high frequency signals are transmitted along the transmission line in the form of electromagnetic waves, the signal line will act as an antenna, and the energy of electromagnetic field will be emitted around the transmission line. The unwanted noise signals between signals due to the coupling of electromagnetic fields are called Crosstalk. The parameters of PCB plate layer, the spacing of signal lines, the electrical characteristics of driving and receiving terminals and the signal line connection mode all have certain influence on the crosstalk. Therefore, in order to reduce the crosstalk of high frequency signals, it is required to do the following as much as possible in the layout process.
I basically copied this from here on Altium website.