Dual-Circularly Polarized Spin-Decoupled Reflectarray With FSS-Back for Independent Operating at Ku-/Ka-Bands

In this work, we propose a new dual-band and dual-circularly polarized spin-decoupled reflectarray (RA) combined with frequency selective surface (FSS)-back that ensure the RA independently operating at
Ku
/
Ka
dual-band. First, a double-layer FSS with four concentric square loops is designed to inhibit the mutual coupling between the
Ku
- and
Ka
-bands. Second, at each
Ku
- and
Ka
-band, the 3 bit coding crossed dipole element is used to realize the spin-decoupling. Moreover, each circularly polarized feed horn generates reflected beam operating with left-hand circular polarization (LHCP)/right-hand circular polarization (RHCP) at
Ku
- and
Ka
-bands, respectively. Finally, the RA with a square size of 340 mm is designed, manufactured, and measured to verify its performance. At 12.45 GHz, the measured cross-polarization levels (XPLs) are better than 16.5 and 18.5 dB for LHCP and RHCP radiations, respectively, which show the great spin-decoupling between the two circular polarizations. The measured XPLs are better than 21 and 22.5 dB for LHCP and RHCP at 30 GHz, respectively. The well-performed RA has the perspective in satellite communication systems at both
Ku
- and
Ka
-bands.