A Low-Profile Dual-Band Circularly Polarized Shared-Aperture Grid-Patch/Fabry–Perot Antenna for CubeSat Applications

A dual-band circularly polarized (CP) shared-aperture grid-patch/Fabry–Perot antenna with a low profile is presented for CubeSat applications. A conducting grid layer is incorporated with a periodic metasurface to act as a partially reflective surface (PRS) of the low-profile Fabry–Perot resonant cavity. A slotted circular patch is used as the feed of the Fabry–Perot antenna to produce high-gain CP radiation in the $X$ band. The grid layer of the PRS is reused as a patch radiator in the $L$ band, which is designed with truncated corners to generate CP radiation. The proposed antenna is implemented on a three-layer substrate without air-gap for a sturdy structure. A fabricated prototype with overall size of $\text{98 mm} \times \text{98 mm} \times \text{3.94}$ mm achieves right-hand CP radiation within 1.230 GHz to 1.242 GHz and 8.0 GHz to 8.4 GHz with an isolation $\ge$ 20 dB. Noting that the frequencies and polarization of the two bands can be easily adjusted by using the same design concept.