A communication device includes a first antenna element, a second antenna element, a third antenna element, a fourth antenna element, a fifth antenna element, a sixth antenna element, a seventh antenna element, an eighth antenna element, and a PCB (Printed Circuit Board). The PCB has a first side and a second side positioned opposite to each other. At least one of the first antenna element, the second antenna element, the third antenna element, the fourth antenna element, the fifth antenna element, the sixth antenna element, the seventh antenna element, and the eighth antenna element is adjacent to the first side of the PCB. The other(s) of the first antenna element, the second antenna element, the third antenna element, the fourth antenna element, the fifth antenna element, the sixth antenna element, the seventh antenna element, and the eighth antenna element is/are adjacent to the second side of the PCB.