An impedance circuit includes an input terminal, a first and a second capacitive arrangement and an output terminal coupled to the input terminal by a network. The network includes the first and the second capacitive arrangement. The first capacitive arrangement includes a varactor circuit having a varactor and at least one series circuit. The at least one series circuit includes a capacitor and a switch in series connection and is coupled parallel to the varactor circuit. The second capacitive arrangement comprises an additional capacitor.