| 摘要 |
An antenna device for a portable radio communication device adapted for receiving radio signals comprises an internal radiating element ( 10 ) comprising at least one feeding portion ( 21, 22 ) connected to a receiver circuit ( 40 ). The radiating element ( 10 ) comprises an electrical impedance ( 30 ) that is controllable in dependence on the desired frequency range of the received signals, wherein the feeding portion ( 21, 22 ) is connected to a feeding input ( 40 a , 40 b) on the receiver circuit and the control input of the controllable electrical impedance ( 30 ) is connected to an output ( 40 c) on the receiver circuit ( 40 ) intended for the control of the VCO resonance frequency of the receiver circuit. In that way an antenna device can be provided inside the casing of a small sized portable radio communication device, which has good performance throughout a narrow sub-band of a frequency band having a relatively low frequency, wherein the narrow sub-band can be adjusted in frequency so as to cover the entire frequency band, such as the FM radio band. |
