Referring to FIG. 2 to FIG. 5, the at least one ground terminal 30 has a fixing portion 301, a touching portion 302 connected with one end of the fixing portion 301, and a soldering portion 303 connected with the other end of the fixing portion 301. Preferably, the at least one ground terminal 30 includes two upper ground terminals 31 and two lower ground terminals 32. The two upper ground terminals 31 have two substantially U-shaped upper fixing portions 311, two upper touching portions 312 slantwise extended rearward and upward, and then arched downward from tops of front ends of the two upper fixing portions 311, and two upper soldering portions 313 slantwise extended rearward and oppositely, and then bent rearward from tops of rear ends of the two upper fixing portions 311. The two upper touching portions 312 are located above the two upper fixing portions 311, respectively. Tail ends of the two upper touching portions 312 approach to root portions of the two upper soldering portions 313, respectively. The two lower ground terminals 32 have two substantially inverted U-shaped lower fixing portions 321, two lower touching portions 322 slantwise extended rearward and downward, and then arched upward from bottoms of front ends of the two lower fixing portions 321, and two lower soldering portions 323 slantwise extended rearward and oppositely, and then bent rearward from bottoms of rear ends of the two lower fixing portions 321. The two lower touching portions 322 are located under the two lower fixing portions 321, respectively. Tail ends of the two lower touching portions 322 approach to root portions of the two lower soldering portions 323, respectively.