Robust 3D Eccentric Field Synthesis for OTA Testing via an Enhanced Spherical Vector Wave Approach

Area of Science:

• Electromagnetics
• Wireless Communication Testing
• Computational Electromagnetics

Background:

• Traditional over-the-air (OTA) testing requires devices at the chamber center, limiting flexible evaluation.
• Spherical vector wave (SVW) methods struggle with eccentric testing due to coefficient-domain overfitting and unstable reconstruction.
• Existing methods like plane wave synthesis (PWS) lack accuracy in eccentric scenarios.

Purpose of the Study:

• To develop a novel method for accurate and stable 3D eccentric field synthesis in anechoic chambers.
• To overcome the limitations of coefficient-domain overfitting in traditional SVW methods for off-center testing.
• To enable flexible and reliable over-the-air testing of modern wireless terminals in non-central positions.

Main Methods:

• Development of a unified 3D eccentric spatial-spectral composite operator.
• Reformulation of the synthesis problem from coefficient-domain fitting to field-domain matching.
• Incorporation of 3D offset directly into the field evaluation process.

Main Results:

• The proposed operator achieves stable, oscillation-free reconstruction under significant eccentric conditions.
• Numerical simulations show the method outperforms PWS by 5-15 dB in accuracy.
• The conventional SVW method fails under significant eccentric conditions, while the proposed scheme maintains performance.

Conclusions:

• The developed spatial-spectral composite operator provides a robust solution for 3D eccentric field synthesis.
• This method enhances numerical stability and accuracy for flexible OTA testing of wireless terminals.
• The findings offer a promising approach for evaluating large-scale wireless terminals in off-center configurations.