LAUSR

A wideband circularly polarized (CP) multi-turns plasma helical antenna (HA) with reconfigurable bandwidth is investigated for wireless communications in the $x$ -band. The proposed plasma-based HA is suitable for integration with electronic circuit components used in system-on-chip applications. A parametric study on the effect of different design parameters on the antenna radiation characteristics is introduced. The antenna dimensions are optimized for wideband CP endfire radiation. The proposed antenna has an impedance matching bandwidth of 48%, a maximum gain of 8.5 dBi, and a wideband CP of 31%. The variation in the number of helix turns improves the antenna gain and bandwidth by changing the plasma frequency. An improvement in antenna gain and radiation efficiency is achieved by loading the antenna with shaped dielectric lenses with a different cross section. The endfire directional gain is improved to 11.5 dBi for hemispherical-shaped lens and 10.5 dBi for a quarter spherical lens with half-power beamwidth (HPBW) of 40°. The finite integration technique (FIT) is used to simulate and analyze the proposed structures.