| 摘要 |
<p>An internal monopole antenna especially intended for flat radio devices. The radiator (320) of the antenna is for the most part in one geometrical plane, forming thus a radiation plane. A planar and conductive ground element (330) is added to the antenna below the radiating plane and parallel with it. This is galvanically connected to the ground plane (310) of the radio device through an inductive element (335), which has relatively high impedance at the operating frequencies of the antenna. The radiator has preferably two branches for forming separate operating bands. The antenna is pretuned upwards so that the effect of both the user's tissues and the ground element, which lowers the resonance frequencies, is taken into account. The antenna is installed in the radio device so that in the operating position of the device it is as far as possible from the user's head with the ground element toward the user. The efficiency of the antenna is relatively good when the device is beside the user's head, the SAR value being small at the same time. In addition, the space between the radiator and the ground element can be utilized by placing other components of the radio device in it.</p> |
