A communication device (1, 4, 5, 6, 7), comprising: a first antenna; a second antenna; and a ground element, coupled to a conductive plane; an isolation element (13, 43, 53, 63, 73), disposed between the first antenna and the second antenna, and comprising a first portion (131, 431, 531, 631, 731) and a second portion (132, 432, 532, 632, 732), wherein a first end of the first portion (131, 431, 531, 631, 731) and a first end of the second portion (132, 432, 532, 632, 732) are respectively coupled to the ground element, and a second end (133, 433, 533, 633, 733) of the first portion (131, 431, 531, 631, 731) is spaced apart a coupling distance (135, 435, 535, 635, 735) from a second end (134, 434, 534, 634, 734) of the second portion (132, 432, 532, 632, 732), wherein the second end (133, 433, 533, 633, 733) of the first portion (131, 431, 531, 631, 731) and the second end (134, 434, 534, 634, 734) of the second portion (132, 432, 532, 632, 732) face to each other, wherein the communication device (1, 4, 5, 6, 7) is configured to operate in at least a first communication band and a second communication band, and wherein a frequency of the first communication band is lower than a frequency of the second communication band, characterised in that the first portion (131, 431, 531, 631, 731) of the isolation element (13, 43, 53, 63, 73) is configured to resonate in the first communication band, and the second portion (132, 432, 532, 632, 732) of the isolation element (13, 43, 53, 63, 73) is configured to resonate in the second communication band, so as to improve isolation between the first antenna and the second antenna in the first communication band and the second communication band. a first antenna; a second antenna; and a ground element, coupled to a conductive plane; an isolation element (13, 43, 53, 63, 73), disposed between the first antenna and the second antenna, and comprising a first portion (131, 431, 531, 631, 731) and a second portion (132, 432, 532, 632, 732), wherein a first end of the first portion (131, 431, 531, 631, 731) and a first end of the second portion (132, 432, 532, 632, 732) are respectively coupled to the ground element, and a second end (133, 433, 533, 633, 733) of the first portion (131, 431, 531, 631, 731) is spaced apart a coupling distance (135, 435, 535, 635, 735) from a second end (134, 434, 534, 634, 734) of the second portion (132, 432, 532, 632, 732), wherein the second end (133, 433, 533, 633, 733) of the first portion (131, 431, 531, 631, 731) and the second end (134, 434, 534, 634, 734) of the second portion (132, 432, 532, 632, 732) face to each other, wherein the communication device (1, 4, 5, 6, 7) is configured to operate in at least a first communication band and a second communication band, and wherein a frequency of the first communication band is lower than a frequency of the second communication band, characterised in that the first portion (131, 431, 531, 631, 731) of the isolation element (13, 43, 53, 63, 73) is configured to resonate in the first communication band, and the second portion (132, 432, 532, 632, 732) of the isolation element (13, 43, 53, 63, 73) is configured to resonate in the second communication band, so as to improve isolation between the first antenna and the second antenna in the first communication band and the second communication band.