Studies On Full-wing Conformal Ultra-wideband Tightly Coupled Phased Array Antenna Techniques

With the rapid development of modern wireless electronic technology,phased array antennas are facing more and more strict challenges,including low profile of antenna arrays,tremendously broadening of working bandwidths and widening of beam scanning angles.Especially for airborne platforms,phased arrays are even required to have conformal or even stealth characteristics.For some platforms with restricted antenna installation spaces,tightly-coupled arrays with merits of ultra-wideband and low-profile are overwhelmingly competitive.On the other hand,conformal antennas are able to fit all sorts of carrier surfaces and even become part of them,thus avoiding the influence on aerodynamic performance of the carriers.Tightly-coupled conformal antenna arrays combine the advantages of tightly-coupled arrays and conformal antennas,thus having the advantages such as ultra-wideband,wide scanning angles,and smaller influence on aerodynamic performance.Consequently,tightly-coupled phased arrays are becoming a research frontier of airborn antennas.Based on the theory of tightly-coupled ultra-wideband phased arrays and the design methods of conformal array antennas,this thesis studied the impedence and radiation characteristics of dual-polarized full-wing conformal tightly-coupled phased array antennas.The thesis then introduces the design of an aforementioned conformal array which achieves wide scanning angle within the bandwith of 5:1 in P-L waveband.The main contents and innovations of this thesis include the following parts:Firstly,the research background and importance of tightly-coupled ultra-wideband phased arrays and conformal arrays are introduced.The development of some tightly coupled planar array antennas and conformal arrays at home and abroad is also briefly summarized.Secondly,the operating theory of tightly-coupled ultra-wideband phased array antenna is presented,and several popular methods of realizing the strong coupling are listed.Meanwhile,the theoretical basis and synthesis methods of conformal array antenna are introduced in detail.Thirdly,based on the one-dimensional conformal array theory,a full-wing conformal dual-polarized tightly-coupled dipole sub-array element working in P-L waveband is propsed and designed,where the up and down surfaces of a section of air-fuselage are fully covered with conformal sub-arrays.After the full-wave simulation and optimal design,the sub-array element is able to achieve an active VSWR of lower than 3.0 within the bandwith of 5:1 while scanning up ±45°.Fourthly,an 1×10 finite full-wing conformal array is designed and simulated based on the aforementioned sub-array element.Simulation results show that the designed conformal array is able to achieve ±45° scaning in azimuth plane for both polarization with an active VSWR lower than 3.0,which satisfies the requirements.Finally,the designed full-wing conformal tightly-coupled ultra-wideband phased array antenna is manufactured,assembled and measured.Measures results are in reasonable agreement with the simulation results,thus verifying the correctness of the design.