| 摘要 |
The present invention relates to a frame antenna (RA), consisting of a frame as an inductance and of a tuning capacitor (C1), which is connected between the frame connecting points (1, 1'), as a capacitance, having a balanced input supply via an impedance converter (IW) whose two secondary supply lines are passed to the frame connection points via in each case one coupling capacitor (C2, C2'). In order to ensure automatic matching over a relatively large frequency range during the resonant tuning process, it is proposed to construct the two coupling capacitors as fixed capacitors. Furthermore, one or more four-pole networks (VP1, VP2) are connected in series with the impedance converter, in the direction of the two coupling capacitors. In this case, each four-pole network (VP1) has in each case one further fixed capacitor (C3, C3') in its two longitudinal branches and an inductance (L1) in its transverse branch. A frame antenna which is equipped with the coupling circuit according to the invention is particularly suitable for use as a transmitting antenna in the short-wave (high-frequency) band. <IMAGE>
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