Circuit board with lower dielectric constant and electrical connector having the same

An electrical connector, comprising a tongue plate, the tongue plate being configured to be mated with a mating electrical connector, the tongue plate comprising a circuit board, the circuit board comprising:

• a first surface;
• a second surface opposite to the first surface, the circuit board comprising a thickness defined by the first surface and the second surface;
• and
• a plurality of metal pads which are arranged on the first surface and/or the second surface;
• wherein the plurality of metal pads located on a same side of the circuit board are arranged at intervals along a first direction, the plurality of metal pads located on the same side of the circuit board comprise a first ground metal pad, a second ground metal pad, and a signal metal pad located between the first ground metal pad and the second ground metal pad;
• and
• wherein the circuit board further comprises an adjustment opening extending through the first surface and/or the second surface along a thickness direction of the circuit board, and the adjustment opening is located beside the signal metal pad along the first direction and is adjacent to the signal metal pad.