Biomimetic direction-sensitive micromachined diaphragm for ultrasonic transducers

This paper presents a novel biomimetic direction-sensitive micromachined diaphragm for ultrasonic transducers. The diaphragm design is based on the mechanical model of the parasitoid fly, Ormia ochracea´s ears which achieve directionality through mechanical coupling of the tympana´s resonant mode shapes. Micromachining technology has been utilized to fabricate the 3D structured biomimetic diaphragm. It has two 60×120×20 μm³ single crystal silicon (SCS) proof masses and solid stiffeners attached to a 0.8-μm-thick silicon nitride diaphragm to create the main resonant mode shapes like the fly´s ears. Acoustic measurements of the diaphragm using laser vibrometry have demonstrated high directional sensitivity of the device