An impedance matching circuit for matching planar antennas includes a signal path with a signal path input and a signal path output. A first capacitive element with variable capacitance is connected between the signal path input and signal path output. A second capacitive element with variable capacitance is connected between the signal path and ground. A first inductive element is connected between the signal path input and ground. A second inductive element is connected between the signal path output and ground. An antenna line with an impedance between 30 and 60 ohm is connected to the signal path output.