Unified Time- and Frequency-Domain Study on Time-Modulated Arrays

Time-modulated arrays (TMAs) are studied in the time domain and frequency domain in this paper. The studies are based on the “instantaneous” array factor as a function of time and “average” array factor as a function of frequency, respectively. The two analysis approaches are shown to be unified and complementary through the Fourier transform. Antenna parameters including pattern, directivity, and gain are all addressed. Moreover, an experimental setup for the study of signal transmission is built and measured. Experimental results are in good agreement with the theoretical study. Finally, the bandwidth of TMAs is taken into account, and amplitude modulation (AM) signal transmission through the TMA is studied experimentally. The results presented in this paper can be used to explain the fundamental working principle of TMAs in a clear and comprehensive way.