Abstract: An apparatus, which includes a local oscillator configured to oscillate at a carrier frequency and having output ports and configured to provide a signal of a respective phase at each of the output ports, wherein the respective phases are different from each other, a plurality of branches, each branch corresponds to one of the output ports and includes a mixer unit, where for each branch, the signal of the respective phase is applied to an input port of the mixer unit and the mixer unit is configured to modulate a baseband signal by the signal of the respective phase of the local oscillator to obtain, at its output port, a respective modulated signal and; a combiner configured to add the modulated signals from the branches to obtain a total signal to be output to a load; and at least one of the branches includes a multi-switch.