Variable Diagonal Loading Based Robust Concentric Hexagonal Antenna Array With Low Side Lobe Level Using Tapering Windows

Abstract

In this paper, the performance of a concentric hexagonal antenna array (CHAA) is investigated with the exploitation of a robust variable diagonal loading (VDL) technique in the presence of direction of arrival (DOA) mismatch. The performance of minimum variance distortionless response (MVDR) based CHAA is compared with the performance of existing MVDR based concentric circular antenna arrays (CCAAs), and it is found that the proposed MVDR based CHAA provides 25.54% narrow half-power beamwidth (HPBW) and lower side lobe level than the existing MVDR based CCAA. When DOA mismatch occurs between main beam steering direction and actual signal-of-interest (SOI) direction, the performance of MVDR based CHAA is deteriorated. In the case of DOA mismatch, to ameliorate the performance of CHAA, this paper proposes VDL technique for the CHAA processor and compares the performance of the proposed robust CHAA with the existing robust CHAAs. The proposed VDL based robust CHAA delivers 88.37% and 78.56% higher output power for 2 • DOA mismatch than existing fixed diagonal loading (FDL) and optimal diagonal loading (ODL) based CHAAs, respectively. Several tapering window functions are proposed to reduce the side lobe level of CHAA. Performance of the proposed beamformer is analyzed utilizing MATLAB environment in various scenarios.

Performance Analysis of Robust Acoustic Circular Microphone Array Beamformer

“…In this paper, VDL and NVL are proposed for their higher output gains and higher SINR. The suggested methods also maintain higher quality with the variation of different values of angle of disparity, the microphone element number, different values of interference direction, different noise power, and filter lengths than the techniques already proposed in [13].…”

“…These robust methods are known as the following: (1) Fixed Diagonal Loading (FDL); (2) Optimal Diagonal Loading (ODL); (3) Variable Diagonal Loading (VDL); (4) New Variable Loading (NVL) [11]. The FDL [12] and ODL [13] have already been discussed with their pros and cons. In this paper, VDL and NVL are proposed for their higher output gains and higher SINR.…”