Worst-Case Performance Optimization Beamformer with Embedded Array’s Active Pattern

Shaode Huang,Jin Pan,Yuyue Luo,J. Andrew Zhang

doi:10.1155/2018/9237321

Abstract

This paper proposes an adaptive array beamforming method by embedding antennas’ active pattern in the worst-case performance optimization algorithm. This method can significantly reduce the beamformer’s performance degradation caused by inconsistency between hypothesized ideal array models and practical ones. Simulation and measured results consistently demonstrate the robustness and effectiveness of the proposed method in dealing with array manifold mismatches.

Highlights

The assumption of ideal array elements in conventional adaptive beamforming technologies can cause severe performance degradation in real implementations due to ignored array imperfections, for increasingly widely used small-profile arrays
Most robust beamforming methods solve uncertain problems based on simplified array models, without considering the array’s electromagnetic characteristics, which are essential to the manifold mismatches and are critical for the performance of the methods in practice
The results clearly show that our adopted radiation expression with active pattern (AP) in (4) approximates the real radiation pattern much better than the one without considering mismatch

Summary

Introduction

The assumption of ideal array elements in conventional adaptive beamforming technologies can cause severe performance degradation in real implementations due to ignored array imperfections (e.g., gain and phase mismatches and mutual coupling between elements), for increasingly widely used small-profile arrays. In [10], improvement to [9] is made by incorporating the antenna’s active pattern (AP) introduced in [11], which calculates an elements’ radiation and its impact on the array environment (both mutual coupling between elements and workspace radiation) [12] These methods rely on the exact knowledge of antennas’ electromagnetic characteristics and are quite sensitive to measurement mismatches. By creatively integrating antenna mismatch modelling into beamforming design, we propose a robust worst-case performance optimization beamformer with an embedded array’s AP We call it as active pattern worst-case (APWC) method which can significantly improve the beamformer robustness under various mismatches. It has better tolerance to both engineering and electromagnetic mismatches caused by elements’ modelling, manufacturing, aperture assembling, and channel debugging

Problem Formulation

Improved Model for Array Steering Vector

Proposed APWC Algorithm

Simulation Results

Measured Results

Conclusion