摘要 |
A monopole antenna for use with at least two wireless communication services, having a monopole element (10) disposed along a straight line (11) and connected with a roof capacitor (1) that is designed as a flat area, the area normal line (12) pointing in the direction of the straight line (11). The roof capacitor (1) has rotational symmetry, and is formed by flat ring structures (2) that are separated from one another by ring-shaped gaps (3), the structures being oriented concentric to the straight line (11). Reactance circuits (4) connect the ring structures (2) with one another so that they are active for a wireless communication service having the lowest frequency, and the outermost ring structure (2) is essentially ineffective for the wireless communication service having the next higher frequency, because of the high impedance of the reactance circuit (4). Likewise, at the higher frequency of the wireless communication services, the outermost ring of the active ring structures (2), connected with one another by means of low impedance reactance circuits (4), is designed to be smaller.
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