Design and implementation of a rectangular frequency invariant beamformer with a full azimuth angle coverage

A novel design of the frequency invariant beamformer based on a rectangular array is proposed with two unique features: there are no taped delay-lines (TDLs) or any other temporal processing involved and the resultant beamformer has a full 360° azimuth angle coverage. This leads to a wideband beamformer with complex-valued coefficients and its implementation is not as straightforward as the traditional ones. Depending on whether the input signal is complex-valued or real-valued, special arrangements and structures are required for its effective implementation. Several design examples are provided with a satisfactory frequency invariant property. Two sets of implementation results are given based on both simulations and data collected by a planar microphone array system.