Electrical connector and circuit board used in the connector

An electrical connector includes a terminal module having a circuit board having first through eighth conductive traces sequentially arranged in a transverse direction and corresponding first through eighth terminals, the third terminal and the sixth terminal being configured for transmitting a pair of differential signals, the fourth terminal and the fifth terminal being configured for transmitting another pair of differential signals, the first through eighth conductive traces being respectively electrically connected to corresponding first through eighth terminals, each of the third conductive trace and the fifth conductive trace including a coupling portion, a size of the coupling portion in the transverse direction is larger than a size of the other part of the corresponding conductive trace in the transverse direction, wherein the coupling portion of the third conductive trace and the coupling portion of the fifth conductive trace overlap in an up and down direction to increase mutual coupling.