Steering vector sensor array elements with linear cardioids and nonlinear hippioids.

The purpose of this work is to study the impact due to individual vector sensor element steering patterns on linear array beamforming. Standard, linear beamformers employ cardioid beampatterns for each vector sensor. In this work, a class of vector sensor element steering patterns beyond the standard cardioid was examined. The element weighting is nonlinear but nonadaptive, making it simple to implement in hardware processing. The new sensor steering patterns, referred to as hippioids, are products of cardioids and various powers of hippopedes. The angular resolution of individual sensors, the impact on angular resolution from arrays of varying aperture, and peak-to-sidelobe levels will serve as performance measures. An example of the differences in vector sensor steering patterns is provided using measured directional frequency and recorded buoy data.