Research Of Continuous Transverse Stub Antenna Array Applied In Mobile Satellite Communication

To adapt to the development of high-throughput satellite communications and meet the demand for real-time communications between satellites and moving platforms,mobile ground station antenna for “Satcom-On-The-Move” system must have the characteristics of high-gain,high-efficiency,low-lost,low-profile and beam scanning.The continuous transverse stub(CTS)antenna is a new type of antenna which could meet these requirements.The design procedure and an exhaustive antenna characterization of CTS antenna are investigated in details.This thesis presents a hybrid structure continuous transverse stub array antenna for Ka-band.The antenna radiation structure and the corporate feed network are built in aluminum where the feeding structure is fabricated in Printed Circuit Board technology.The author's major contributions are as follows:Firstly,the CTS antenna element based on stepped impedance matching structure is designed.The influences which the variation of structural parameters of CTS antenna elements have on VSWR and radiation pattern are discussed.Simulated results show that the antenna element achieves high-gain and wide-band.Then,the parallel feed network based on parallel plate waveguide is designed.The procedure of forming array is researched.The CTS antenna array with input port of wide-side waveguide which consists of the antenna elements and the parallel feed network is designed.Simulated results show that the CTS antenna array has characteristics of wide-band,high-gain,and low-sidelobe.Secondly,the feeding structure of CTS array antenna which is made up of H-plane horn antenna array and the pillbox beamformer is researched.The H-plane horn antenna array with rectangular patch based on SIW has excellent characteristics of impedance matching and radiation pattern,which could meet the requirement of beam scanning for CTS array.The pillbox beamformer could convert the incoming cylindrical wave into a planar wave with excellent phase characteristics,which satisfies the CTS array feeding demand of planar wave.The influences which H-plane horns with different loaded aperture have on the quality of plane wave and radiation pattern are analyzed.The influences which the variation of structural parameters of pillbox beamformer have on radiation characteristics are discussed.Finally,the designed CTS antenna array is simulated and measured.The measurements are in good agreement with full-wave simulation results.The results show that an input reflection coefficient better than-10 d B is obtained in the 26.5-31.5GHz band for all scanning positions.At the center frequency of 29 GHz,the gain reaches 28 d Bi,the sidelobe level of H-plane is-32.64 d B,and the antenna efficiency exceeds 80% in the whole scan range.The antenna scan losses lower than 2d B are reported at ±30°.The normal gain variation is less than 2d B in the design frequency band.The features of the radiation pattern are stable within the design 26.5–31.5GHz band.The designed CTS antenna array has characteristics of wideband,high-gain,high-efficiency,low-sidelobe,low-profile and beam scanning,which meets the demand of communications for “Satcom-On-The-Move” system.