Abstract: A phase shifter is fed an input signal having a frequency f. A coupler is included fed by the input signal. The coupler has a pair of output terminals for providing a pair of signals having the frequency f and having a relative phase shift difference of m?/2 radians, where m is an integer. A switch is included having a pair of inputs, each one of the pair of inputs being coupled to a corresponding one of the pair of output terminals of the coupler. The switch has an output, one of the pair of inputs of the switch being coupled to the output of the switch selectively in accordance with a first control signal fed to the switch.