3D Beam Steering End-Fire Helical Antenna With Beamwidth Control Using Plasma Reflectors

In this article, a beam steerable antenna based on plasma reflectors is presented. The proposed antenna consists of an axial mode helical antenna surrounded by an array of plasma reflector elements forming a cup-shaped ground. In this configuration, the elements of the reflector array can be individually switched on or off to achieve different radiation characteristics for the helical antenna. Specifically, it is shown that the symmetric activation of a specified number of elements of the plasma array can be used to control the beamwidth of the antenna. Moreover, the plasma reflectors can be asymmetrically configured to steer the endfire beam pattern of the helical antenna in 3-D space. To validate the concept, the proposed antenna is designed and numerically simulated. The simulation results show that using the proposed method, the beamwidth of the proposed antenna can be changed from 37° to 50° while the beam direction can be altered in 3-D space within a solid angle of ±6°. Finally, a prototype of the designed antenna is fabricated and its radiation characteristics for various configurations of the plasma reflectors are measured. Good agreement between the simulation and measurement results validates the proposed method.