Wireless communication devices, such as mobile phones or personal digital assistants (PDAs), mainly use monopole antennas or inverted-F antennas. However, these antennas must have a corresponding keep-out-zone. Then, it is an important issue for people to design an antenna in a limited keep-out-zone, wherein the antenna has a low frequency band of about 704-960 MHz, a high frequency band of about 1710-2690 MHz, and has good radiation characteristics.