A sequential actuator for a radio frequency switch, the actuator comprising:
- a rotor designed to be rotated in a designated rotational direction about an axis of the actuator in a stepped rotation between a plurality of latched angular positions that are substantially equally spaced apart angularly about the axis;
- a stator;
- and
- a plurality of magnetic elements distributed between the rotor and the stator, each of the rotor and the stator having at least one of the magnetic elements, the rotor including a plurality of protruding rotor magnetic elements angularly positioned about the axis and the stator including a plurality of protruding stator electromagnetic elements angularly positioned about the axis and at least one coil configured to energize all of the stator electromagnetic elements simultaneously, the distributed magnetic elements defining a detent torque curve of the rotor defined by the torque applied on the rotor due to the interaction of the magnetic elements distributed between the stator and the rotor when the stator electromagnetic elements are not energized, the detent torque curve including a plurality of detent stables zeroes wherein each detent stable zero defines one of the latched angular positions;
- wherein at least one of the stator electromagnetic elements and the rotor magnetic elements are unevenly distributed angularly about the axis whereby when the stator electromagnetic elements are energized, the stator electromagnetic elements and the rotor magnetic elements define an active torque curve of the rotor having asymmetric positive and negative torque curve portions, wherein the active torque curve is defined to include a non-zero positive torque curve portion and a non-zero negative torque curve portion between each adjacent pair of latched angular positions, and the non-zero positive torque curve portion and the non-zero negative torque curve portion between each adjacent pair of latched angular positions are asymmetric, the active torque curve defined by the torque applied on the rotor at any given angular position through the interaction between the stator electromagnetic elements and the rotor magnetic elements when the stator electromagnetic elements are energized due to the tendency of the rotor to rotate towards angular positions of reduced reluctance;
- wherein the stator electromagnetic elements and the rotor magnetic elements are distributed angularly about the axis to define the active torque curve to comprise angular positions of the rotor defining a plurality of active stable zeros and a plurality of active unstable zeros, the active stable zeros corresponding to angular positions where the rotor magnetic elements are angularly aligned with the stator electromagnetic elements, the active unstable zeros corresponding to angular positions where each rotor magnetic element is positioned at a midpoint between two stator electromagnetic elements;
- wherein the stator electromagnetic elements and the rotor magnetic elements are unevenly distributed angularly about the axis whereby a positive portion of the active torque curve within an angular range defined between two adjacently positioned active unstable zeros has an angular with that is different from an angular width of a negative portion of the active torque curve within the angular range;
- and
- wherein the sequential actuator is a single phase actuator.