Planar superdirective microphone arrays for speech acquisition in the car

In this paper we investigate a small broadside planar (2D) superdirective microphone array for speech acquisition in the car and compare its performance to linear arrays. The objective of this investigation is to replace an expensive directional microphone by a small array of inexpensive omnidirectional sensors. Since the array was designed to be used in the car environment it has to satisfy restrictions with respect to size and to the number of microphones. For all array configurations we present theoretical gains, actual measured gains using low-cost microphones, and beam patterns. For a fixed number of microphones and fixed array dimensions we show that the planar design leads to slightly superior array gains.