Joint Calibration of Non-Uniform Element Patterns and Phase States for Accurate Control of Radiation Patterns in Time-Modulated Arrays

The time modulation technique is a promising method for accurate control of amplitude-phase weightings in antenna arrays. Traditional time-modulated arrays (TMAs) face challenges in determining modulation parameters for practical hardware with non-ideal factors like non-uniform element patterns and imperfect phase states, which will greatly hinder the applications of TMAs in active phased array systems. This paper proposes a hardware-based inverse time sequence design model that considers the effect of non-ideal factors in practical antenna and time modulation modules, improving the precision in the control of both equivalent amplitude and phase. Therefore, the proposed method also enables accurate control of sidelobe levels (SLLs) and enhances the beam pointing accuracy at the antenna array level. The proposed inverse design model is applied to a 4×32 linear antenna array operating in the Ku-band. Both numerical and experimental results demonstrate that the antenna array is capable of achieving an accurate beam steering within a scanning range of ±50° and an accurate low SLL of -20 dB in the radiation pattern, thus verifying the effectiveness of the method.