US Patent 11356084 Low-loss bi-directional passive LSB phase shifter in mm-wave CMOS

A phase shifter with a first port and a second port has a triple inductor network with a center inductor connected to the first port and the second port, and first and second peripheral inductors each electromagnetically coupled to the center inductor. A resistance switch network that is connected to the first and second peripheral inductors. The resistance switch network is selectively activatable to set a first state defined at least by a first resistance in a series circuit with the first and second peripheral inductors, a second state defined at least by a second resistance in the series circuit, and a third state defined at least by a third resistance in the series circuit. A transmission signal from the first port to the second port is shifted in phase by a prescribed angle corresponding to forward transmission coefficients for the first state, second state, and third state.