Sidelobe Suppression Beamforming Using Tapered Amplitude Distribution for a Microwave Power Transfer System with a Planar Array Antenna

• Published in: Journal of Electromagnetic Engineering and Science Vol. 22; no. 1; pp. 64 - 73
• Main Authors: Park, Inho, Seo, Chulhun, Ku, Hyunchul
• Format: Journal Article
• Language: English
• Published: 한국전자파학회JEES 01.01.2022; The Korean Institute of Electromagnetic Engineering and Science; 한국전자파학회
• Subjects: array factor; digital beamforming; microwave power transfer; sidelobe suppression; wireless power transfer; 전자/정보통신공학; Wireless Power Transfer; Microwave Power Transfer; Sidelobe Suppression; Array Factor; Digital Beamforming
• ISSN: 2671-7255; 2671-7263; 2671-7263
• DOI: 10.26866/jees.2022.1.r.62

This paper proposes a sidelobe suppression beamforming scheme using tapered amplitude distribution for microwave power transfer (MPT) with a two-dimensional planar array antenna (PAA). To overcome the undesirable effects of sidelobes, the magnitude of the sidelobes can be lowered by manipulating the amplitude distribution of the PAA. By analyzing the array factor of the PAA, we expressed the amplitude distribution as the product of two one-dimensional vectors. Moreover, we developed a method for obtaining these vectors from an expected sidelobe level (SLL). We used the Chebyshev taper, which has a higher directivity than other distributions given an expected SLL, for the amplitude distribution. To verify the proposed method, we designed and implemented a digital beamforming system with a 4 × 4 transmitter (Tx) array and a receiver (Rx) at 5.8 GHz. Compared with a uniform amplitude distribution, the proposed method reduced the SLL by 7.5 dB but the received RF power by only 0.6 dB. We compared the performance of the proposed MPT system with the results of previous studies.