Design of Sum and Difference Patterns with Common Nulls and Low SLLs Simultaneously in the Presence of Array Errors

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

8 Scopus Citations
View graph of relations


  • Yanhong Xu
  • Xiaowei Shi
  • Anyi Wang
  • Jingwei Xu


Original languageEnglish
Pages (from-to)934-944
Journal / PublicationIEEE Transactions on Antennas and Propagation
Issue number2
Online published9 Nov 2018
Publication statusPublished - Feb 2019


Sum ( Σ ) and difference ( Δ ) beampatterns are commonly utilized to estimate the bearings of targets in radar system. However, the nulls of Δ -pattern are not always aligned with those of Σ -pattern and this phenomenon would become more severe in practical scenario since the array errors exist. Meanwhile, the sidelobe level (SLL) of the array would also increase due to the unavoidable errors. The above described factors would dramatically decrease the performance of radar in adaptive suppression of interference. To increase the output signal-to-interference-plus-noise ratio (SINR) of radar system, this paper presents an approach to design the low SLL ΣΔ -patterns where the nulls of the Δ -pattern, excluding the central null, are always aligned with those of the Σ -pattern in the presence of errors. Two schemes are addressed to obtain the covariance matrix for null-alignment constraint (CM-NAC), which is exploited to force nulling in desired angles accordingly. In the sequel, matrix tapering method is adopted to broaden the nulls and enhance the robustness for the possible errors. With the proposed approach, the low SLL and nulls alignment can be achieved simultaneously. Numerical examples are provided and discussed to demonstrate the effectiveness of the proposed solution, including the results based on a linearly spaced microstrip array antenna.

Research Area(s)

  • array errors, Array signal processing, Covariance matrices, covariance matrix for null-alignment constraint (CM-NAC), Force, Interference, Radar, Radar antennas, sidelobe reduction, Signal to noise ratio, Sum and difference patterns

Citation Format(s)