Research On Broadband Wide-angle Low-RCS Phased Array Antennas

Phased array antennas have been widely used in the military and civilian fields.They can realize advanced functions such as fast beam scanning,adaptive beam forming and anti-interference,high-precision search and tracking.The future electronic platform will cover multiple functions such as electronic reconnaissance,electronic interference,radar detection,and wireless communication.On the other hand,facing the increasingly complex and severe battlefield environment,the stealth technology of electronic platforms puts forward stricter restrictions on the number of antennas carried and the RCS of the antennas.Therefore,the future phased array antenna should have the characteristics of broadband operation,wide-angle scanning,and low RCS.An in-depth study on broadband wide-angle low-RCS phased array antenna is carried out.The main work of this doctoral dissertation is summarized as follows:Two planar broadband wide-angle phased array antennas are proposed.A probe-fed dipole phased array antenna with parasitic patches is proposed,which overcomes the difficulty of matching planar dipole antennas,and a compact probe-fed structure is proposed.The infinite array achieves 45.2%bandwidth with active VSWR<2 when scanning to±60°in E-plane,±60°in D-plane,and±50°in H-plane.The profile of the array is 0.145?_high.In order to further realize wider bandwidth and wider scanning range,a substrate-integrated broadband wide-angle slot phased array antenna is proposed.An accurate equivalent circuit model is established to analyze the broadband principle of the antenna.An air gap is introduced between the wide-angle matching layer and the radiating structure,which not only improves the impedance matching performance,but also suppresses the propagation of surface waves.The phased array antenna achieves 65.2%bandwidth with active VSWR<2 when scanning to±60°in all azimuth planes.Both phased array antennas have the characteristics of broadband,wide-angle,low cost and low profile.A broadband wide-angle scattering structure based on artificial dielectric layers is proposed.The reflection performances of the scattering structure and the RCS reduction performance of the scattering surface are studied,which provides support for the subsequent research on the low-RCS phased array antennas.First,the bandwidth of the180°reflection phase difference of the traditional scattering structure is broadened by loading artificial dielectric layers,the designed scattering elements achieve 180°±37°reflection phase difference in the frequency range of 4.8?17.5 GHz.The reflection phase performances of the scattering elements at different incident angles are analyzed,and a design scheme is proposed to keep the anti-phase characteristics basically stable under different incident angles.Further,a broadband wide-angle scattering surface is designed and fabricated,which achieves a more than 10 d B bistatic RCS reduction at normal incidence within 112.7%bandwidth.At TE 40°and TM 55°incidence,the10-d B bistatic RCS reduction bandwidths are 110.9%and 101.8%,respectively,good oblique incidence performance is achieved.A broadband wide-angle low-RCS phased array antenna with artificial dielectric layers is proposed.The scattering structures and the slot phased array antenna are organically integrated.The RCS reduction function is organically integrated into the wide-angle matching layers without increasing total profile,insertion loss and processing difficulty.Based on the sub-array technology,the frequency gap between the operating frequency band and the RCS reduction frequency band is eliminated.The proposed infinite array can scan to±60°in E-plane and±40°in H-plane in the frequency range of 2.5?4 GHz.The fabricated finite array achieves broadband wide-angle characteristics,and an ultra-wideband monostatice RCS reduction over the frequency range of 4?26 GHz is also achieved.A low-RCS tightly coupled dipole array antenna with polarization selective metasurface is proposed.First,a polarization selective metasurface is designed,which achieves an ultra-wideband 180°reflection phase difference in the frequency range of3.74?15 GHz;then,a scheme for the integration of the polarization selective metasurface and the tightly coupled dipole antenna is given.The RCS reduction of the tightly coupled dipole array antenna is achieved without affecting the antenna radiation performance and increasing the profile.At the same time,the influence of the antenna structure on the scattering cancellation is avoided.The proposed infinite array can scan to±60°in all azimuth planes in the frequency range of 6.5?12 GHz.The fabrecated finite array achieves broadband wide-angle characteristics,and an ultra-wideband monostatic RCS reduction in the frequency range of 3.9?15.1 GHz is also achieved.