| Antipad |
The clearance gap between a via pad and the surrounding metal plane (copper pour) in which it is located. |
| Coplanar transmission line |
A transmission line consisting of a signal conductor and a signal return path (conductors or pours) located on the same layer of the printed circuit board. |
| Differential pair |
Two conductors driven with equal and opposite alternating voltages and currents. |
| Embedded transmission line |
A transmission line consisting of a signal conductor located on an inner layer of the printed circuit board and a single reference plane (potential layer) that serves as the signal return path. |
| Even mode |
The condition of a differential pair in which the voltages on the two lines are equal (same polarity). |
| Microstrip transmission line |
A transmission line consisting of a signal conductor located on an outer layer of the printed circuit board and the nearest reference plane (potential layer) that provides the signal return path. The signal conductor and the reference plane are separated by the PCB dielectric. |
| Odd mode |
The condition of a differential pair in which the voltages on the two lines are opposite (opposite polarity). |
| Reference layer |
A layer used exclusively for solid metal planes (copper pours) that occupy the entire layer area — typically used to connect components to ground and power nets. |
| Stripline transmission line |
A transmission line consisting of a signal conductor located on an inner layer of the printed circuit board and two reference planes (potential layers) that provide the signal return paths. In this configuration, there are two return paths for the signal. |
| Transmission line |
A system of signal and return conductors consisting of a signal trace and a signal return path, which typically runs through a reference plane (potential layer). |