A Compact Multiple Flat-topped Beams Antenna based on Butler Matrix

• Published in: 2022 IEEE/CIC International Conference on Communications in China (ICCC) pp. 565 - 569
• Main Authors: Wang, Chuangkai, Zheng, Shaoyong
• Format: Conference Proceeding
• Language: English
• Published: IEEE 11.08.2022
• Subjects: Antenna feeds; Antenna measurements; Butler matrices; Butler matrix; Cutoff frequency; Flat-top; Metals; multi-beam antenna; nonuniform array antenna; Power dividers; Scattering parameters
• DOI: 10.1109/ICCC55456.2022.9880841

A 1\times 16 nonuniform array antenna with multiple flat-topped beams is proposed in this paper. To excite the array antenna, a 4\times 16 feeding network based on Butler matrix and power dividers is also designed. The multi-flat-topped patterns are realized by combining the patterns of a 1\times 10 subarray and three 1\times 2 subarrays. A differential evolution algorithm is applied to further optimize the ripples and cut-off rates of the multi-flat-topped patterns. The log-periodic bow-tie antenna is chosen as the antenna element due to its flat-topped active element patterns. Metal strips are added on the ground plane to improve isolation between elements. For verification, both the array antenna and feeding network are fabricated and measured. The active S-parameters of almost all elements are smaller than -10 dB from 9.6 GHz to 10.4 GHz. Four flat-topped beams with ripples of 1.8 dB and cut-off rate of 4.1 dB/°are achieved across the operating frequency.