| Millimeter-wave with the characteristic of abundant and pure spectrum resources can perfectly meet the working bandwidth requirement of the high-speed wireless communication system.In addition,in order to meet the demands for the system to enhance signal capture ability and suppress multipath interference,it is no doubt that millimeter-wave circularly polarized beam-scanning antenna array is a good choice.Therefore,this paper is focused on the research of millimeter-wave broadband circularly polarized beam-scanning antenna array,including two research aspects about V-band broadband end-fired circularly polarized multibeam antenna array and Ka-band broadband circularly polarized phased array antenna.1.V-band wideband end-fired circularly polarized multibeam antenna: the problem with limited beam coverage of existing millimeter-wave circularly polarized multibeam antennas is studied in this paper.A novel wideband end-fire circularly polarized element with a wide axial ratio(AR)beamwidth is proposed firstly.Based on the analysis of the surface current of the radiation aperture of the antenna element,the wideband operating principle of the antenna element is studied.In addition,the connection hole can reduce the mutual coupling between the array elements with slightly increasing the element spacing to guarantee the beam coverage and axial ratio performance of the multibeam antenna.The Butler matrix is used to feed to the multibeam antenna array.The broadband circularly polarized multibeam antenna is finally achieved a 3-dB axial ratio bandwidth of 57 GHz to 73GHz(relative AR bandwidth of 24.6%),and a wide beam coverage ranging from 45° to 66°.The V-band circularly polarized multibeam antenna proposed in this paper has the merits of a wide AR bandwidth and wide beam coverage,so it is suitable to apply in high-speed wireless communication systems such as WiGig and WPAN.2.Ka-band wideband circularly polarized phased array antenna: A broadband slotcoupled circularly polarized antenna element is proposed in this paper.Two orthogonal modes of the cross slot is excited by the L-shape strip line to generate the circularly polarized wave.For the problem with AR performance deterioration of the beamscanning circularly polarized antenna array,the back cavity is added to suppress the surface wave and improve the AR performance in the large beam-scanning angle.In addition,a rotary feed layout is used to improve the AR performance in a small beam-scanning angle.The Ka-band circularly polarized phased array antenna is finally achieved an AR bandwidth of 28GHz~32GHz(relative AR bandwidth of 13.3%)under the condition of 45° beam-scanning angle.The Ka-band circularly polarized phased array antenna proposed in this paper has a wide AR bandwidth and excellent beam-scanning performance,so it is suitable to apply in Ka-band satellite communication system. |
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