As mobile communication technology advances, mobile devices have become more and more popular. Portable computers, mobile phones, multimedia players, and other portable electronic devices with multiple functions, have become ubiquitous with their growing popularity. In order to satisfy consumer demands, incorporating wireless communication capabilities in those devices is a must. Some of the wireless communication methods cover longer ranges, such as 2G, 3G, and LTE (Long Term Evolution), which are widely being used in mobile phones that operate in frequency bands of, for instance, 700 MHz, 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, 2100 MHz, 2300 MHz, and 2500 MHz. On the other hand, some of the wireless communication methods cover shorter ranges, like Wi-Fi and Bluetooth systems that usually operate in frequency bands including 2.4 GHz, 5.2 GHz, and 5.8 GHz.
A capable antenna is a critical component to support wireless communications in such mobile devices. However, antenna efficiency is easily affected by the environment such as dense metal components disposed near or around the antenna. Taking an example of conventional multi-mode portable apparatuses, while operating in different modes, the relative position change of the built-in antenna with regard to other metal components easily causes interference with or otherwise impacts the radiation of the antenna and thereby lowers the communication quality. As a result, new solutions for overcoming these drawbacks are strongly desired.