Design of low profile and variable pitch angle helical antenna for maritime satellite communications

In order to meet the demand of Satcom-on-the-move(SOTM) antennas for maritime satellite communication terminals,the design of low profile and variable pitch angle of helical antenna is proposed in this paper.The proposed antenna is made of copper foil supported by foam.Under the circumstance of a given antenna height,the performance of circular polarization of the antenna is enhanced by changing the pitch angle and the input impedance matching is improved by adjusting the microstrip stub.The design method of the antenna is given,and the optimal antenna structure is obtained after a large of electromagnetic simulations.The designed antenna is fabricated and measured.The measured results show that in the whole maritime satellite communication work band the VSWR is less than 1.12,its antenna gain is higher than 9dBi,and the axial ratio is lower than 3dB.The experimental results have a good agreement with the simulations.The antenna has the characteristics of light weight,low pro-file and easy tuning.It provides a novel antenna element structure for SOTM antenna array in maritime satellite communication applications.