High-order Superdirectivity of Line Acoustic Vector Sensor Arrays

Quantitative Analysis Method and Correction Algorithm Based on Directivity Beam Pattern for Mismatches between Sensitive Units of Acoustic Dyadic Sensors

“…According to the Taylor series expansion theory of sound pressure [4], complete sound field information includes sound pressure (scalar, zero-order spatial partial derivative), sound pressure gradient or acoustic particle velocity (vector, first-order spatial partial derivative), second-order sound pressure gradient or particle velocity gradient (dyadic, second-order spatial partial derivative) and higher order information. Additionally, the higher the order of the measured sound field information, the higher the directivity of the acoustic detection system [5][6][7][8][9][10][11], so as to meet the application requirements.…”

“…Equation (10) describes the estimated value of the acoustic particle velocity gradient at the acoustic center of the ADS when the amplitude, phase and axis of the two sensitive units are all mismatched. From Equation (10), the directivity beam pattern of the sensor can be obtained when there is only a single mismatch, so as to better show the influence of various types of mismatches on the directivity of the ADS.…”

“…When there are two types of mismatches between two sensitive units at the same time, their normalized directivity beam patterns of the particle velocity gradient derived from Equation (10) are shown in Figure 7 (𝐿 𝜆 ⁄ 0.01). As illustrated in Figure 6, for L/λ = 0.01, the directivity of the ADS is also sensitive to the axial mismatch of the two particle velocity sensing units, and the change in beam pattern caused by axial mismatch is complicated too.…”

“…When there are two types of mismatches between two sensitive units at the same time, their normalized directivity beam patterns of the particle velocity gradient derived from Equation (10) are shown in Figure 7 (L/λ = 0.01).…”