ALEXANDRIA, Va., Feb. 3 -- United States Patent no. 12,539,984, issued on Feb. 3, was assigned to Northwestern University (Evanston, Ill.) and Board of Regents, The University of Texas System (Austin, Texas).

"Battery-free unmanned aerial vehicle" was invented by Josiah David Hester (Evanston, Ill.), Rishabh Goel (Evanston, Ill.), VP Nguyen (Arlington, Texas) and Tien Pham (Arlington, Texas).

According to the abstract* released by the U.S. Patent & Trademark Office: "Unmanned aerial vehicles are provided. In one aspect, the unmanned aerial vehicle includes a four-bar linkage mechanism in mechanical communication with a pair of wings. An electrical subsystem includes an actuator in mechanical communication with the four-bar-linkage mechani...