1. Field of the Invention
The invention relates to an antenna, more particularly, to a multi-band antenna for receiving various frequency bands.
2. The Related Art
An antenna for receiving and transmitting wireless signal is an important component in wireless device. Nowadays, wireless communication bands at telecommunication field includes: global system for mobile communications (GSM) band about 850 mega-hertz (MHz), extended global system for mobile communications (EGSM) band about 900 MHz, digital cellular system (DCS) band about 1800 MHz, personal conferencing specification (PCS) band about 1900 MHz, and international mobile telecommunications-2000 (IMT-2000) about 2100 MHz.
There are various types of antennas for the portable communication device to use, such as helix, monopole, inverted-F, dipole, patch, loop and retractable antennas. Helix antenna and retractable antenna are typically installed outside the portable communication device. Inverted-F antenna, monopole antenna, patch antenna, loop antenna and dipole antenna are typically embedded inside the portable communication device case or housing.
Generally speaking, the embedded antennas are more preferable than the external antennas for the portable communication device owing to mechanical and ergonomic reasons. Embedded antennas are protected by the wireless device case or housing and therefore tend to be more durable than external antennas. Therefore, the embedded antenna capable of operating at various wireless communication bands such as GSM band, EGSM band, DCS band, PCS band and IMT-2000 band is required, to become an essential component for the portable wireless communication device.