We introduce a meta-surface cavity into the waveguide slot array design and demonstrate the perfect generation of dual-circularly polarized (CP) dual-beams, where the cavity consists of meta-surface coated dielectric substrate surrounded by metallic vias and metal walls. When integrated with the rectangular waveguide, the meta-surface cavity functions as the leaky wave passage, capable of coupling the linearly polarized incidence from the feed into the cavity and releasing the resonant mode with birefringent radiations of right-hand and left-hand CP waves. Our design, performing the beam splitting and polarization conversion simultaneously as a waveguide slot array, should pave the way for building up more advanced meta-surface-based architectures for the manipulations of electromagnetic fields in the transmission regime.

A method to suppress cross-band scattering is presented in this letter. A two-antenna system is analyzed, which consists of a lower-band (LB) dipole and a higher-band (HB) dipole. A pair of sleeves is loaded on the arms of the LB dipole. The cross-band scattering between the HB and LB antennas close to each other usually deteriorates the pattern of the HB antenna. In the proposed antenna system, the sleeves loaded on the arms of the LB dipole are used to suppress the induced current on the LB antenna and reduce the cross-band scattering in the two-dipole system, which restores the radiation pattern of the HB antenna. A prototype of the proposed antenna system is fabricated and measured. The results show that the maximum radiation direction of the HB antenna is changed from a maximum of 24 degrees back to 0 degrees in H-plane.

Sandwiched frequency selective surface (FSS) is proposed as an additional reflection surface for a dual-frequency reflectarray system. The range of reflection phase for a reflectarray depends on the substrate thickness sensitively. Usually, a tradeoff between the smooth linear level and the wide reflection phase range is needed, especially for a dual-frequency system. By inserting an FSS between the ground plane and the reflecting element layer, a selective plane for the dual-frequency band is provided. For the higher frequency band, the FSS layer is a reflection plane. For the lower frequency band, it is transparent and the reflection plane is changed into the metal ground plane. A dual-band reflectarray with a scattering angle of 30 degrees is simulated and measured to validate this concept.

A dual circular polarization Fabry–Pérot resonant antenna is proposed in this paper. The proposed antenna consists of a microstrip antenna radiator and meta-surface. Meta-surface is applied into the design of a Fabry–Pérot (FP) resonant cavity for generating two circularly polarized (CP) beams. When the meta-surface functions as a partially reflecting surface with a top C-gaps array, dielectric substrate with holes periodically arranged around the atoms and bottom metal plate with strip gaps, the proposed design would split an LP wave from the feed into the left-hand CP and right-hand CP waves by rotating the top C-gaps to form prescribed phase gradients. Simulation and measurement results show that the proposed antenna is capable of generating left-hand CP and right-hand CP radiation beams pointing at 18° and −18° at 14.9 GHz with a stable gain of over 22.7 dBic and an aperture efficiency of 25.7%. The proposed technique offers an efficient way to fulfill FP resonant antennas with specific characteristics using meta-surface for more advanced functionalities.