Communication device

A communication device comprising:

• a metal back cover electrically connected to a system ground plane;
• a first antenna unit configured to generate a first operating frequency band of the communication device, the first antenna unit includes:
• a first metal frame connected to the metal back cover via a first connecting portion and connected to the system ground plane via an active circuit ;
• and
• a first signal source electrically connected to the first metal frame via a first matching circuit;
• a second antenna unit configured to generate a second operating frequency band of the communication device, the second antenna unit includes:
• a second metal frame connected to the metal back cover via a second connecting portion, a first gap is formed between the second metal frame and the first metal frame;
• a second signal source electrically connected to the second metal frame via a second matching circuit;
• and
• a fourth signal source electrically connected to the second metal frame;
• wherein the first matching circuit and the second matching circuit are configured to adjust bandwidths and frequency ratios of the first operating frequency band and the second operating frequency band;
• a third antenna unit configured to generate a third operating frequency band of the communication device, the third antenna unit includes:
• a third metal frame connected to the metal back cover via a third connecting portion, a second gap is formed between the third metal frame and the second metal frame;
• and
• a third signal source electrically connected to the third metal frame via a third matching circuit, the third matching circuit is configured to adjust the bandwidth and the frequency ratio of the third operating frequency band;
• a fourth antenna unit configured to generate the second operating frequency band of the communication device, the fourth antenna unit includes:
• a fourth metal frame connected to the metal back cover via a fourth connecting portion;
• and
• a fifth signal source electrically connected to the fourth metal frame via a fifth matching circuit;
• and
• a fifth antenna unit configured to generate the first operating frequency band of the communication device, the fifth antenna unit includes:
• a fifth metal frame connected to the metal back cover via a fifth connecting portion, and connected to the system ground plane via a second active circuit, a third gap is formed between the fifth metal frame and the fourth metal frame;
• and
• a sixth signal source electrically connected to the fifth metal frame via a sixth matching circuit;
• wherein the fifth matching circuit and the sixth matching circuit are configured to adjust the bandwidths and the frequency ratios of the second operating frequency band and the first operating frequency band.