Characterization and Compensation of Nonideal Effects of Modulation Functions in Time-Modulated Array for Direction-of-Arrival Extraction

Abstract

This article investigates nonidealities of the time modulation function that may affect the measurement accuracy when extracting the direction of arrival (DOA) using the time-modulated array. The types of nonidealities are identified and the fundamental and harmonic Fourier coefficients for each type are calculated theoretically. The measurement DOA error is calculated using these Fourier coefficients, and the allowable bounds of the nonideal parameters guaranteeing the confidence region of the error are proposed. Furthermore, a two-step measurement procedure is proposed to reduce these errors. For a systematic reduction of the measurement errors, a method for characterizing and compensating the nonidealities is investigated. To verify the validity of the proposed theory and measurement method, experiments are conducted to compare the results with and without calibration and compensation.