Abstract: Transmission of control information from one location in a solid structure o one or more remote locations in that structure is accomplished with ultrasonic surface waves transmitted along the structure. The ultrasonic carrier is frequency-modulated to cause the resulting standing wave patterns in the structure to be spatially shifted at the modulation frequency and thereby avoid permanent vibration nodes at receiver locations. The invention has particular utility in munitions structures.

Abstract: Disclosed herein is an antenna system for use with small projectile nose es (metal). The antenna comprises a wedge shaped metallized dielectric material having an electrical length equal to one-quarter wavelength as measured inside the center line of the wedge. The metallic coating covering both the top and bottom of the wedge is provided to form a parallel plate radiator. The metallic coating is also extended across the base of the wedge to define an RF short circuit at the base and an open circuit at the apex. An RF coupling probe extending into the wedge is located at a convenient impedance matching point near the base of the wedge. The operating frequency of the antenna may be capacitively tuned (either electrically or mechanically) by means of a variable capacitor connected across the open circuit end (the apex) of the antenna. Typically the dielectric comprises teflon-fiberglass or ceramic material although an air dielectric is also usable.