Independent Amplitude/Phase-Manipulation Metasurface Based on BLRFC Scheme and Its Application to Wideband Metalens Antenna With Side-Lobe Suppression

In this work, based on the scheme using the antenna array back-loaded radio frequency circuit (BLRFC) to realize circuit level manipulation, a novel design of amplitude/phase manipulation metasurface (A/PMMS) is proposed. The BLRFC has been used to manipulate transmissive electromagnetic (EM) waves by loading control circuits between the grounds of two antenna arrays. Based on the proposed A/PMMS, the amplitude and phase of EM waves can be manipulated independently. The phase manipulation is realized by tuning the length of the transmission line. And the amplitude manipulation is realized by tuning the characteristic impedance of the transmission line to change the match between the circuit and the antennas. Furthermore, a wideband metalens antenna with side-lobe suppression is designed, fabricated and measured based on the proposed scheme. The side-lobe suppression is achieved by tuning the amplitude distribution of the metalens aperture to realize the Taylor distribution. Measurements show that the proposed metalens antenna achieves the 3-dB gain bandwidth of 35.8 % (8 - 11.5 GHz). At 9 GHz, the first and the second side-lobe levels (SLLs) in the E- and H-planes are suppressed lower than - 30 dB, and the realized gain is 23.6 dBi. The measured performance verifies the flexibility and the superiority of the novel scheme. In addition, the proposed scheme can be easily extended to the dual-polarized design. By using dual-polarized antennas, and loading circuits on the channel of each polarization, a dual-polarized A/PMMS is designed. The proposed dual-polarized A/PMMS can independently manipulate dual-polarized EM waves. To the authors’ best knowledge, this type of A/PMMS has not been reported.