Right Angle wiring is generally required to avoid the situation in PCB wiring, and it has almost become one of the standards to measure the quality of wiring, so how much impact will right Angle wiring have on signal transmission? In principle, right-angle wiring will cause the line width of the transmission line to change, resulting in impedance discontinuity. In fact, not only right Angle wiring, ton Angle, acute Angle wiring may cause impedance changes.
    The impact of right-angle wiring on the signal is mainly reflected in three aspects: first, the corner can be equivalent to the capacitive load on the transmission line, slowing down the rise time; Second, impedance discontinuity will cause signal reflection; The parasitic capacitance brought about by the right Angle of the transmission line can be calculated by the following empirical formula: C=61W (Er) 1/2/Z0 In the above formula, C refers to the equivalent capacitance of the corner (unit: pF), W refers to the width of the line (unit: inch), εr refers to the dielectric constant of the medium, and Z0 is the characteristic impedance of the transmission line.
    As the line width of the right-angle line increases, the impedance there will decrease, so a certain signal reflection phenomenon will be generated, we can calculate the equivalent impedance after the line width increase according to the impedance calculation formula mentioned in the transmission line chapter, and then calculate the reflection coefficient according to the empirical formula: ρ= (ZS-Z0)/(Zs+Z0), generally the impedance change caused by right-angle wiring is between 7% and 20%, so the reflection coefficient is maximum about 0.1.