This disclosure provides systems, methods and apparatus for electromechanical systems having sidewalls beams. In one aspect, a device includes a substrate having a first electrode and a second electrode, and a movable shuttle monolithically integrated with the substrate, and having a first wall, a second wall, and a base. The first and second walls each have a first dimension at least four times larger than a second dimension. The first and second walls define substantially parallel vertical sides of the shuttle, and the base is positioned orthogonally to the first and second walls and forms a horizontal bottom of the shuttle, providing structural support to the first and second walls. The first wall and the first electrode define a first capacitor, and the second wall and the second electrode define a second capacitor.