In this paper we present a passive and cost-effective method for increasing the frequency range of ultrasound MEMS microphone arrays when using beamforming techniques. By applying a 3D-printed construction that reduces the acoustic aperture of the MEMS microphones we can create a regularly spaced microphone array layout with much smaller inter-element spacing than could be accomplished on a printed circuit board due to the physical size of the MEMS elements. This method allows the use of ultrasound sensors incorporating microphone arrays in combination with beamforming techniques without aliases due to grating lobes in applications such as sound source localization or the emulation of bat HRTFs.

翻译：本文提出一种被动式且经济高效的方法，用于在使用波束成形技术时扩展超声微机电系统麦克风阵列的频率范围。通过采用3D打印结构来减小微机电系统麦克风的声学孔径，我们能够创建规则间距的麦克风阵列布局，其阵元间距远小于印刷电路板上因微机电元件物理尺寸限制所能实现的间距。该方法使得采用麦克风阵列的超声传感器能够结合波束成形技术，在声源定位或蝙蝠头相关传输函数仿真等应用中，避免因栅瓣效应引起的信号混叠问题。