Tool Introduction

A stripline is a copper strip placed in the middle of a dielectric between two conductive planes. If the thickness and width of the line, the dielectric constant of the medium, and the distance between the two conductive planes are controllable, then the characteristic impedance of the line is also controllable. Crosstalk is the unwanted coupling energy between traces. There are two types: forward and backward. This tool calculates reverse crosstalk, which is usually the dominant crosstalk component.

Description

Stripline: Walking on the inner layer (stripline/double stripline), the stripline buried inside the PCB, as shown in the figure below:

The blue part is the conductor, the green part is the insulating dielectric of the PCB, and the stripline is a strip-shaped conductor embedded between two layers of conductors.

Because the stripline is embedded between two layers of conductors, its electric field distribution is between the two conductors (planes) that wrap it, and it will not radiate energy or be interfered by external radiation. However, since it is surrounded by dielectrics (dielectric constant is greater than 1), the signal transmission speed in the stripline is slower than in the microstrip line!

The stripline is a copper strip line placed in the middle of a dielectric between two layers of conductive planes. If the thickness and width of the line, the dielectric constant of the medium, and the distance between the two layers of conductive planes are controllable, then the characteristic impedance of the line is also controllable.

Stripline: The signal layer is between two solid planes (voltage or ground). Stripline can achieve better RF radiation prevention, but it can only be used at lower transmission speeds. Because the signal layer is between two solid planes, there will be capacitive coupling between the two planes, which will reduce the edge rate of high-speed signals. The capacitive coupling effect of stripline is more significant for signals with edge rates faster than 1ns. The main effect of using stripline is to completely shield the RF energy of the internal trace, so it has better suppression ability for radio frequency.

It should be noted that radiation will still be generated from other components. Although the internal trace can prevent it from radiating, other internal edges (bond wiring, component pins, sockets, internal wiring and other similar ones) will still cause problems. With the impedance of the system, components, and traces, there will be impedance mismatch problems. This mismatched impedance will cause RF energy to couple from the internal trace to other circuits or free space. Minimizing the lead impedance of the component pins can reduce radiation.

Crosstalk is unwanted coupled energy between traces. There are two types of crosstalk: forward and backward. This tool calculates backward crosstalk which is usually the dominant crosstalk component.

Backwards crosstalk creates a pulse width that is twice that of the propagation time of the pulse traveling the coupling distance. The amplitude of this crosstalk is what this tool calculates. The amplitude increases as the coupling length increases up to a point. At some point the amplitude will stay constant. The crosstalk coupling calculation requires information for the driver source as well as the PCB physical characteristics. This tool calculates the crosstalk coefficient as well as the coupled voltage, both can be useful in crosstalk analysis.