Microstrip fed planar endfire circularly polarised antenna with enhanced bandwidth

摘要

A wideband planar endfire circularly polarised loop antenna is proposed. The antenna is fed by a microstrip line with a novel ground plane instead of a coaxial probe. The microstrip line part and the loop part generate the vertical polarisation and the horizontal polarisation, respectively. Two stubs added on the loop contribute to the bandwidth improvement. The proposed antenna achieves wide impedance bandwidth (|S11| <; -10 dB) and wide 3-dB axial ratio bandwidth, both of which can cover the frequency range from 8.0 to 12.5 GHz (43.9%).