Airborne phased array for airborne applications based on celular polymer

Object recognition, advanced distance measurements and other inspection scenarios have an increasing demand in versatile airborne ultrasonic phased arrays for acoustic scanning without moving parts. Based on cellular polymer film with high piezoelectric effect of up to 150 pC/N we have realized an array structure with a pitch of 0.5 mm and element length of 10 mm. The working frequency of the material was measured to 250 kHz. A first prototype of 32 elements was realized. From pointspread simulation with the small ratio of pitch/wavelength of 0.35 we could expect good beam steering and focusing characteristics. The array was characterized and the results are in good agreement with the simulations. Measurements showed that cellular polymer is a well suitable material for airborne applications. It can easily be structured to the desired shape. It allows especially the realization of Phased Arrays for applications like surface or profile measurement, access control, attend ance check, robot guidance etc.. With this technology many array types like linear, phased, curved or circular arrays are possible. The elements of the array can be curved to optimize the elevational beam characteristics. Also single element transducers with varying geometry of apertures (rectangular, oval), shaped apertures (focusing (line- or point-focusing), defocusing) or combinations of both are possible.