Right-angle alignment is generally required in the PCB layout to avoid the situation, and almost become a measure of good or bad one of the standards, then the right-sided alignment of the signal transmission will have much impact? In principle, the right-sided alignment will make the transmission line width changes, resulting in impedance discontinuity. In fact, not only right-angle alignment, Dangqi, acute angle alignment may cause changes in the situation of the impedance.
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Right angle alignment of the signal is mainly reflected in three aspects: First, the corner can be equivalent to the transmission line on the capacitive load, slow rise time; Second, the impedance will cause a continuous reflection of the signal; Third, (E) is the equivalent capacitance of the corner (unit: pF), where C is the equivalent capacitance (unit: pF) of the corner, and C is the equivalent capacitance of the corner (unit: pF). In the above equation, C is the equivalent capacitance of the corner (unit: pF) W refers to the width of the trace (unit: inch), εr refers to the dielectric constant of the medium, Z0 is the characteristic impedance of the transmission line.

As the line width of the right-angled line increases, the impedance at that point will decrease, resulting in a certain signal reflection. We can calculate the equivalent impedance after the increase in linewidth according to the impedance calculation formula mentioned in the chapter on the transmission line. According to the empirical formula to calculate the reflection coefficient: ρ = (Zs-Z0) / (Zs + Z0), the general diagonal line caused by the impedance change between 7% -20%, so the maximum reflection coefficient of 0.1 or so.