Dual-Band Antenna with OAM Mode Radiated by Ground Plane

Abstract

Antennas that radiate orbital angular momentum (OAM) modes are usually large and have complex structures. In this paper, in combination with characteristic mode analysis, the ground plane is used as the OAM wave radiator. To excite degenerate modes of the ground plane with phase quadrature by using a single-fed structure, two bent metal strips with grounded ends are introduced around the rectangular ground plane, and a corner of one of the bent strips is set as the feeding point. For ground radiators, a first-order OAM mode is generated at the high-frequency end by synthesizing the degenerate modes. In case of the bent side strip, an inverted-F antenna that operates in the low-frequency mode is formed. This compact antenna has dual-band characteristics and facilitates simple feeding, which makes it suitable for mobile terminal applications.