Single-Layer Circular Polarized Endfire Antenna Based on HMSIW and Quasi-Yagi

Based on the theory of half mode substrate integrated waveguide (HMSIW) and Quasi-Yagi, this paper proposed a single-layer planar circular polarized endfire antenna. The antenna is composed of HMSIW and Yagi structure. The HMSIW can generate vertically polarized wave radiation in the endfire. The Yagi antenna can generate horizontally polarized wave radiation in the endfire. After effectively controlling the relationship between amplitude and phase, the antenna can achieve endfire circular polarization. Moreover, single-layer planar structures are more likely to be conformal to carriers such as airplanes. Within the impedance bandwidth of the antenna, the axial ratio is less than 3dB, meeting the requirements of modern communication systems.