| 摘要 |
<p>An internal antenna (300) having at least two operating bands especially intended for small radio apparatuses. The antenna comprises a directly fed monopole-type basic element (310) and a short-circuited parasitic element (320). The elements are conductor patterns on the surface of a low-loss and thin substrate (301). Between them, at many different points (31, 32, 33), there is a significant electromagnetic coupling. In addition, both elements have separately adjacent portions between which there is a significant electromagnetic coupling. The elements can be branching, in which case said portions can be located in different branches. The couplings are implemented so that each element together with the other element has at least two usable resonances. The resonances of the antenna are quite independent from each other also at frequencies below 1 GHz, which enables constituting a wide operating band in the range in question covering a frequency range used by more than one system. Furthermore, the antenna is very small-sized, and its feed point (FP) and short-circuit point (SP) can be arranged in the middle area of the structure, the omnidirectionality then being good.</p> |
