All MEMS microphones have an omnidirectional pickup response, which means that they respond equally to sounds coming from any direction. Multiple microphones can be configured in an array to form a directional response or a beam pattern. A beamforming microphone array can be designed to be more sensitive to sound coming from one or more specific directions than sound coming from other directions.
Microphone beamforming is a rich, complex topic. This application note is only intended to cover the basic concepts and array configurations, including broadside summing arrays and differential endfire arrays. It covers design considerations, spatial and frequency responses, and advantages/disadvantages of different array configurations.