Modeling and Mitigation of Time Delay Error for Non-Timed Arrays in Satellite Communications

Abstract

A hybrid electromagnetics and communications model is proposed to quantify the performance degradation of non-timed array antennas (e.g. phased arrays or reflectarray antennas) from time delay induced errors. Partial mitigation techniques are investigated. As a non-timed array increases in size, steering angle, frequency, or symbol rate the signal degradation due to lack of true time delay compensation increases from the combined effect of the various per-element fractional time delays. The authors propose that the signal degradation from intersymbol interference due to timing effects can be thought of as an efficiency term and be used to assign a relative energy per symbol to noise power spectral density (EsNo) degradation based on standard satellite communications protocols (specifically DVB-S2X) with an assumed acceptable link margin. From these results, design recommendations are proposed for maximum array size, steering angle, and symbol rate for assumed operating conditions in satellite communications. The work also explores how partial mitigation techniques (e.g. equalization-based, spatial-based or amplification-based approaches) might be applied to the problem as an alternative to true time delay.

Keywords

• Intersymbol interference
• non-timed array
• phased array
• reflectarray
• satellite communications
• time delay