[IEEE 2018 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC) - Xuzhou (2018.7.21-2018.7.24)] 2018 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC) - Three Methods to Generate Orbital Angular Momentum Beams in Microwaves

摘要： This paper reviews three methods to generate orbital angular momentum (OAM) beams in microwave region. Circular patch array, Vivaldi connecting array and microstrip ring antenna are the potential candidates. The first two utilizes phased array technique, which needs complex feeding network, while the later method uses the higher modes of microstrip ring. Vortex OAM beams can be observed in all the methods.