Patent ID: 7366310

Claim:
A microphone apparatus of comprising: an array of microphones, each producing a separate signal; a processor for combining the separate signals of said microphones to provide an output signal representing a steerable beam; and a diffracting structure located at least partly within said array of microphones and configured to increase the effective path length across said array; and wherein said processor combines said separate signals with complex weights W m based on the location of said individual microphones and taking into account the modifying effect of said diffracting structure, and wherein said complex weights are set according to the equation W m =exp( iωτ m ) wherein the time delays τ m are set according to the equation ωτ m =−arg[ F ( r m ,r 1 )] wherein F represents the sound field around said microphone array, r m represents position of microphone m and r 1 represents an arbitrary observation position described in coordinates from an origin within the array.