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/spl times/120/spl times/20 /spl mu/m/sup 3/ single crystal silicon (SCS) proof masses and solid stiffeners attached to a 0.8-/spl mu/m-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.