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

In this paper, 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 general linear frequency modulation (LFM) are investigated in a four-branch TMAPWMB module. The analysis and numerical results exhibit the attractive capability in the suppression of unwanted harmonic component in radio-frequency (RF) channels. Then, the proposed TMAPW-MB modules are employed in an X-band 1×16 Vivaldi antenna array for amplitude-phase weighting and, therefore, beamforming. The numerical results show that radiation patterns with -25.0 dB sideband levels (SBLs), -20.0 dB sidelobe levels (SLLs), and ±50° beam scanning range could be realized through the proposed TMAPW-MB module. Meanwhile, due 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.