Electric-Field Pattern Measurements of Acoustically Driven Piezoelectric Field Emitters

Piezoelectric transmitters operating at acousticalresonance have been shown to radiate effectively in the VeryLow Frequency (3 kHz to 30 kHz) and Low Frequency regime(30 kHz to 300 kHz). Such transmitters make use of the inversepiezoelectric effect to couple electrical signals into mechanicalvibrations, resulting in near field radiation. This new class ofelectrically small antennas, known as mechanical antennas or‘mechtennas’ can provide several orders of magnitude higherefficiency than similarly sized electrically small conventionaldipoles. Measuring the dipole-like near field pattern of suchpiezoelectric field emitters in the Very Low Frequency and LowFrequency range using conventional techniques is not possible.To address this limitation, a simple capacitor plate-based setupis presented that enables the measurement and plotting of thenear field patterns of such transmitters. Design and simulationof the capacitor plates to model the fields along with electric fieldpattern measurements of a Y 36◦ cut Lithium Niobate transmitterhaving longitudinal mode resonance at 82 kHz are presented.