A generator including a power combiner is provided. The power combiner includes a plurality of inputs, each input connectable to a respective power amplifier for receiving a respective power signal. A plurality of impedance matching circuit branches is connected to a respective one of the plurality of inputs. Each impedance matching circuit branch includes at least one high pass filter section and at least one low pass filter section through which the respective power signal passes. The impedance matching circuit branches are connected so as to combine the power signals from each power amplifier. An output is provided for outputting the combined power signal.