Circularly polarised equilateral triangular patch antenna for mobile satellite communications

A left-handed circularly polarised (LHCP) triangular patch antenna is developed to support the next generation of mobile satellite communications using Engineering Test Satellite VIII (ETS-VIII). The targeted minimum gain of the antenna is set to 5 dBic for applications of a hundred kbps data transfer with an axial ratio less than 3dB for circular polarisation. A dual-proximity-coupled equilateral triangular patch antenna is proposed and simulated by the method of moments (MoM) for finite and infinite ground plane models to investigate the ground plane effect. Then measurements of the fabricated antenna are performed to confirm the simulation results. The measurement results show that the frequency characteristics of the fabricated antenna is 0.2% shifted to the higher frequency, and the maximum gain is 0.45 dB lower than the result of the finite ground plane model. Additionally, the simulation results show the ground plane size influences the antenna characteristics, especially the gain and axial ratio of the developed antenna.