A detachable antenna module (100) is provided for attachment to a wireless communication device (102) that has a built-in antenna (300). The detachable antenna module (100) includes an external antenna (104), an activation control mechanism (106), and at least one attachment feature (200) for removably attaching the antenna module (100) to the communication device (102) such that the antenna module and the communication device form a single mobile unit when attached. The activation control mechanism (106) selectively electrically couples the external antenna (104) to the communication device (102) when the antenna module is attached to the communication device, so as to selectively route signal transmission and/or reception through either the built-in antenna (300) of the communication device (102) or the external antenna (104) of the antenna module (100) when the antenna module is attached to the communication device. Also provided is a wireless communication device that includes a built-in antenna and such an antenna module.