US Patent 10122251 Sequential actuator with sculpted active torque

A sequential actuator for a radio frequency switch includes a rotor designed to be rotated in a designated rotational direction of the actuator and a stator defining with the rotor when the stator is energized an active torque curve of the rotor having asymmetric positive and negative torque curve portions. Magnetic elements are distributed between the rotor and the stator and define a detent torque curve of the rotor. In some examples, when the stator is energized, the rotor undergoes a first rotation from a position of partial angular overlap of a first rotor magnetic element with a first stator electromagnet to a position of angular alignment of the first rotor magnetic element with the first stator electromagnet. Upon reaching this angular position, a second rotor magnetic element has a partial angular overlap with a second stator electromagnet and the rotor further undergoes a second rotation to another position of angular alignment of the second rotor magnetic element with the second stator electromagnet.