Enhancement of axial ratio‐beamwidth of X‐band composite microstrip patch antenna with conical ground plane

Abstract

A single-feed circularly polarised (CP) composite microstrip patch antenna (MPA) with a 3D conical ground plane at X-band is presented here to meet the requirements of wide beamwidth for on-board antenna structures of highly rotating bodies in projectile motion. The results of the measurement for fabricated antenna in the anechoic chamber show that a half power beamwidth > 120 ° and axial ratio (AR) beamwidth > 100 ° are achieved for right-hand CP radiation pattern in both the xoz and yoz planes with a gain of ∼ 2 dBi . The AR at the resonating frequency of 10.28 GHz has a low figure of 0.46 dB producing nearly smooth CP foot print with a wide AR beamwidth. The measured reflection coefficient ( S 11 ) of CP–MPA is < − 15 dB at 10.28 GHz with an impedance bandwidth that is 8.75% of the resonant frequency. The figure of merit for cross-polarisation in the fabrication is ∼ 18 dB , i.e. achieved at the zenith of co-polarisation.