Modeling of nonideal characteristics in 2-bit time-modulated arrays

To minimize the performance discrepancy between practical time modulated arrays (TMA) and ideal models, we develop a nonideal mathematical model of 2-bit TMA in this work. The proposed nonideal model comprehensively considers a variety of nonideal characteristics of a practical 2-bit TMA, including transient switching effects of radio-frequency (RF) switches, amplitude-phase imbalances among RF channels, and mutual coupling, edge effects and polarization purity of antenna elements. With the proposed nonideal model, nonideal time modulation pulses are generated to accurately simulate the radiation performance of a practical 2-bit TMA. Numerical analysis and experimental validations for a Ku-band 2-bit TMA prototype are presented to demonstrate the effectiveness of the proposed nonideal model. As compared to ideal models, the proposed nonideal model exhibits higher accuracy in predicting sideband levels, cross-polarization levels, and gain losses. It provides a reliable way to analyze the radiation performance of practical 2-bit TMA.