A Parasitic Antenna with Independent Pattern, Beamwidth and Polarization Reconfigurability

Abstract

In this paper, a reconfigurable antenna design is proposed to realize independent pattern, beamwidth and polarization reconfiguration at an operating frequency of 2.45 GHz. This antenna is comprised of a dual coaxial-feed driven element surrounded by four varactor loaded size-tunable parasitic elements. The pattern and beamwidth reconfiguration is achieved by utilizing the mutual coupling between the active and size-tunable parasitic elements. Reconfigurable feeding network is designed and developed to produce two orthogonal linear polarization (LVP, LHP) and circular polarization (LHCP, RHCP) states. In linear polarization operating mode, main beam of the antenna is continuously scanned from = 0 ◦ to 11◦ , 0 ◦ to 32◦ , and 0 ◦ to 40◦ in = ±0◦ , ± 45◦ , and ± 90◦ plane respectively, where and are the beam direction in the elevation and azimuth planes respectively. In circular polarization operating mode, the radiated beam is continuously scanned from 0 ◦ to 30◦ in = ± 0 ◦ , ± 45◦ and ± 90◦ plane respectively with axial ratio less than 3 dB in all the beam scanning directions. In addition to this, 3-dB beamwidth is continuously tuned in the E-plane, H-plane, and both E-plane and H-plane with LVP and LHP operating mode from 66◦ to 152◦ , 60◦ to 108◦ , and 78◦ to 120◦ respectively.