In this paper, a simple metasurface superstrate structure is proposed to reduce mutual coupling of both E-plane and H-plane coupled patch antennas. The proposed metasurface is consisted of periodic ring slots arranged on one side of the substrate. The metasurface can suppress the surface wave and partly change the coupling mode, which can achieve isolation enhancement of more than 40dB at resonant frequency in both E/H plane coupled patch antennas. The edge-to-edge spacing between antenna elements is 2mm ( $0.023 \lambda_0$ ). The prototypes of E-plane and H-plane arrays with metasurfaces are fabricated, and the experimental measurements and the simulation results are in good agreement.

A novel broadband microstrip helical antenna array with 1*8 elements is designed based on traditional helical antenna. The helix is realized by connecting stacked multilayer microstrip circular arcs with via holes. Meanwhile, grounded coplanar waveguide(GCPW) to stripline is utilized for probe station measurement. The simulated impedance and radiation pattern are studied. The proposed antenna shows a wide impedance bandwidth from 9.8to12GHz for |S 11 |<-10dB, with wide 3dB beamwidth of E-plane about 120 0 , respectively.