Abstract
A novel cavity backed circularly polarized antenna with a square radiating aperture for broadband characteristics is presented in this paper. The horizontal and vertical components of the antenna are separated and fabricated on the front and back side of the substrate. The antenna is excited by a microstrip line which is connected to vertical component of the L-shaped probe and electromagnetically couples the signal to the horizontal component of the L-shaped probe. Broadband circular polarization (CP) with unidirectional patterns can be obtained by having a square cavity of height λ_g/4 behind the antenna. A measured bandwidth of 44.8% (2.65-4.18GHz) in S11 with 44.97% (2.69-4.25GHz) in axial ratio (AR) characteristics along with an overlapped bandwidth of 43.38% is achieved.
