Independent Control of Multiple Harmonic Beams in Time-Modulated Arrays With Subarrayed Time-Segmented Pseudorandom Modulation

The inherent multiharmonic characteristics of time-modulated antenna arrays (TMAs) offer significant potential for generating multiple beams under a single radio frequency (RF) chain. However, the amplitudes and phases at different harmonic frequencies are often mutually affected, which poses challenges for independent control of multiple harmonic beams. To address this issue, this article introduces a novel multibeam TMA with subarrayed time-segmented pseudorandom modulation (STPM). By dividing the ideal continuously varied modulating waveforms into multiple time segments and approximating these time-segmented waveforms with pseudorandom modulation, the proposed STPM enables subarrays to achieve accurate amplitude-phase weightings at different harmonics. Multibeam radiation in this case could be obtained by the superposition of the harmonic beams of different subarrays. Benefiting from the low-sideband property inherited from pseudorandom modulation, the proposed SPTM effectively reduces the amplitude-phase dependence among different harmonics. A multibeam pattern synthesis strategy is then developed to analytically determine the instantaneous modulation statuses of antenna elements for specified beam-scanning angles and sidelobe levels (SLLs). Compared with state-of-the-art TMAs, the presented TMA facilitates high-precision, real-time, and independent multibeam control with a significantly reduced number of modulation statuses in time modulation modules.