| 摘要 |
A transfer unit (4) for transferring a radio frequency signal between a classical antenna tuner (1) and an antenna (6, 23) where the transfer unit (4) comprises a switch (9, 10) for alternatively selecting a first direct route for the radio frequency signal between the tuner (1) and the antenna (6, 23) or a second route via a reactive element; said reactive element comprising a variable serial capacitance and a shunt inductance connected to system earth; and where a control unit (20) controls the switch (9, 10) and is adapted to select the first route when the frequency is above a predetermined value and otherwise select the second route. The variable serial capacitance comprises a set of capacitors (11, 12, 13, 14) organized as a set of binary weighted parallel capacitance values, and the transfer unit (4) further comprises switches (15, 16, 17, 18) to engage or disengage each capacitor from the reactive element to increase or decrease the resulting capacitance as the radio frequency is decreased or increased. The control unit (20) can use a subset of the capacitors (11, 12, 13, 14) for one range of frequencies and a different subset of the capacitors (11, 12, 13, 14) for a different range of frequencies. The control unit (20) can alternatively measure the radio frequency by means of a sensor (21) or receive frequency values via a data link (7). |
