A High Selectivity Filter Antenna Array for Generating Dual-Mode OAM

A reconfigurable high selectivity filter antenna array based on a single-layer design is introduced to be produced vortex beams. The filter antenna array is composed of eight-antenna element and the presented filter antenna element mainly consists of a patch with V-shaped slots, two shorting pins and defected ground structures. The patch with V-shaped slot provides a rapid roll-off rate near the higher frequency band. When the additional shorting pin are introduced, a radiation null is observed at the lower frequency band. The simulation results show that the proposed OAM filter-antenna array has a flat gain about 5.4 dB in the passband of 4.9~5.8 GHz. However, in the stop band, a deed radiation null of -18.74 dB can be observed, which shows a high suppression level and a good skirt selectivity. Moreover, the 3-D gain-pattern and the spatial phase distribution show the proposed filter-antenna array can be produced vortex beam with filtering characteristics efficiently.