Harmonic Beamforming in Antenna Array with Time-Modulated Amplitude-Phase Weighting Technique

In this work, a novel module named time-modulated amplitude-phase weighting with multiple branches (TMAPW-MB) is proposed to realize harmonic beamforming. The harmonic beamforming is then explored to eliminate the conventional digital phase shifters and digital attenuators in antenna arrays. The input and output of a general linear frequency modulation (LFM) is investigated in a four-branch TMAPW-MB module. The analysis and numerical results exhibit the attractive capability in the suppression of unwanted harmonic component in RF channels. Then, the proposed TMAPW-MB modules are employed in an X-band 1W16 Vivaldi antenna array for amplitude-phase weighting and therefore beamforming. The numerical results show that radiation patterns with -25.0 dB sideband levels (SBL), -20.0 dB sidelobe levels (SLL), and ±50° beam scanning range could be realized through the proposed TMAPW-MB module. Meanwhile, owing to the removed quantization errors in traditional digital phase shifters and digital attenuators, the proposed module ensures real-time, continuous beam scanning and precisely controlled SLL and SBL in antenna arrays.