RCS and Side Lobe Reduction for OAM Vortex Beam of Antenna Array Using EBG Structures

A new configuration aimed at reducing radar cross section (RCS) and generating Orbital Angular Momentum (OAM) vortex beam at 7.15GHz by patch antenna array is proposed. The configuration structure is composed of polarization-dependent mushroom Electromagnetic band-gap (EBG) cells, which are designed as traditional chessboard pattern. EBG cell gets near 180 degrees +/- 30 degrees phase difference, which is widely used as basic structure of low RCS reflector. The proposed antenna array is composed of eight circular patches, which are designed as a circle to generate OAM beam. Then, EBGs with chessboard pattern are applied to the antenna array to reduce RCS in-band dramatically and reduce the side lobe of radiation pattern at center frequency of the reference antenna array at the same time. Simulation results show that compared with the reference antenna array, the proposed antenna array obtains a 10dB RCS reduction during the working frequency band for both x-polarization and y-polarization. Meanwhile, the proposed antenna array gets 2.6dB lower side lobe at 7.15GHz, which lead to a better property of OAM.