A Low-Mutual Coupling Dual-Band Dual-Reflectarray Antenna With the Potentiality of Arbitrary Polarizations

In this letter, a novel dual-layer dual-band reflectarray element is proposed, which consists of two different topologies: the cross-dipoles with fixed-size rings for Ku-band, and the round patches with variable-size rings for Ka-band. By optimizing the corresponding parameters, the dual-band reflectarray element can achieve not only sufficient phase variation with gentle slope, but also low mutual coupling. Furthermore, the dual-band operation can be obtained with arbitrary polarization due to the symmetric structure of the element. Afterward, a dual-reflectarray antenna with the proposed dual-band element is designed, fabricated, and measured for the first time. The results of measurement agree with that of simulation very well. The measured peak gains are 28.57 dBi at 35 GHz and 24.3 dBi at 16 GHz, respectively. Moreover, the cross polarizations at both bands are under –20 dB. The measured and simulated results indicate the good radiation performance of the antenna, which is a good candidate for dual-band monopulse antenna.