A W-Band High-Efficiency Multibeam Circularly Polarized Antenna Array Fed by GGW Butler Matrix
Caixia Wang, Yuan Yao, Xiaohe Cheng, Zhongbo Zhu, Xiaojun Li
Abstract
In this letter, a high-efficiency multibeam circularly polarized (CP) antenna array with the groove gap waveguide (GGW) feeding technology for W-band application is proposed. First, a wideband CP septum antenna element based on GGW structure is proposed. The antenna has a simple structure with high tolerance, and the GGW technology reduces the machine difficulty, making the antenna easier to work in the higher frequency. Next, a 4 × 4 GGW Butler matrix is designed to feed the antenna array. Finally, a high-efficiency W-band four-beam CP endfire antenna array is fabricated and measured. Measured results verify that the antenna has a wider impedance bandwidth of 17.6% from 77.5 to 92.5 GHz for |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | <; -10 dB. The measured AR values of the main lobe range of four beams are almost less than 3 dB. Also, stable radiation patterns are obtained. The maximum gain and radiation efficiency are 15.29 dBic and 89.6%, respectively.