C-/Ka-Band Low-Profile Circularly Polarized Shared-Aperture Antenna for CubeSat Communications

This communication presents a low-profile circularly polarized (CP) shared-aperture antenna at C- and Ka-bands for CubeSat communications. It consists of a C-band metasurface antenna and a $4\times 4$ Ka-band magnetoelectric (ME) dipole antenna array and only has $0.057\lambda _{low}$ thickness. The square ring reactive impedance surface (RIS) and an irregularly shaped driven patch are meticulously designed in the C-band antenna without affecting the radiation performance of the Ka-band antenna. Meanwhile, a sequential rotation feeding network (SRFN) is adopted for the Ka-band antenna to improve the axial ratio (AR) performance. The measured results show that the overlapped operational bands ( $\vert $ S $_{\mathbf {11}} \vert \lt -10$ dB and AR <3 dB) are 11.4% (6.2–6.95 GHz) for the C-band and 36.7% (26–37.7 GHz) for the Ka-band, with realized peak gains of 9.36 and 17.2 dBic, respectively. The isolations of the shared aperture antenna within the two operating bandwidths are both better than 20 dB. With the excellent advantages of low profile and dual wideband, the proposed antenna is suitable for various communication applications in CubeSats.