  The electrohydrodynamic (EHD) force produced by ions ejected from a corona
plasma is a solid state, silent mechanism for accelerating air, useful for
applications ranging from electronics cooling to flying microrobots. This paper
presents the theoretical motivation and the first implementation of a
multi-stage, highly miniaturized EHD device, which can provide both improved
absolute power output and power density as compared to single-stage devices. A
laser microfabricated, folded electrode design reduces component count and
assembly time. Data from one, two, and three-stage devices demonstrates a near
linear scaling of output force with stage count, indicating inter-stage ducting
successfully reduces losses. Device lifetime is assessed to validate the use of
stainless-steel emission electrodes. Areal thrust, force density, and
volumetric power density for the three-stage device are among the highest ever
measured from an EHD actuator.
