A Low-Profile Metasurface-Inspired Antenna With Tilted Beam Radiation

In this letter, a simple method of generating tilted beam radiation through a planar structure is presented based on mode synthesis. Under the guidance of this operating principle, a low-profile metasurface-inspired antenna emitting tilted beam is designed with the aid of characteristic mode analysis. The radiation structure of this antenna is a printed nonuniform metasurface. A broadside radiation mode is supported by an etched slot while a bidirectional radiation mode is excited by a metal via with a parasite microstrip line simultaneously. Consequently, a tilted beam radiation can be obtained by combining these two modes. To verify the analysis and simulation, the metasurface antenna is fabricated and tested. Measurement result indicates that this proposed metasurface antenna can realize a tilted beam at 5.1 GHz towards 35$^\circ$ with a realized gain of 7.9 dBi and a low profile of 0.048$\lambda _{0}$ ($\lambda _{0}$ is the operating wavelength in free space).