Abstract: A low-profile wide-beam dual-band circularly polarized (CP) shared-aperture antenna with high aperture reuse efficiency is proposed in this paper. The antenna adopts the structure reuse design concept, plans the topology layout and designs different types of antenna elements. The top layer uses microstrip ring antenna and works in the band of unmanned aerial vehicle (UAV) data transmission (1430-1444 MHz). The bottom layer uses microstrip circular patch antenna and works in the band of UAV remote control (2408-2440 MHz). The ring patch is not only a low-band radiator, but also serves as a high-band director for beam control to achieve wide beam characteristics. Simulated and measured results show that the antenna has good impedance matching and CP radiation characteristics with the impedance and axial ratio bandwidth both cover the two operating bands of UAV communication. At the same time, the height is only 0.07λ0. Therefore, a widebeam dual-band CP shared-aperture antenna with a compact structure and controllable performance is realized, which has application value in UAV communication systems.