| Conformal array antenna has intrigue widely interests in aerospace and aeronautics because of its wide radiation coverage and little influence by aerodynamic characteristics of the antenna carrier.As a typical conformal antenna array,antenna wrapped around a conical surface structure is constrained by three dimensions: circumference,generatix direction and conical angle.The synthesying processing of conformal antenna array pattern is difficult with the increase of constraints.Therefore,the realization of large-scale scanning of conformal antenna array in conformal antenna array pattern systhesis has always been a problem to be overcome in the field of conformal antenna research.As conical conformal array antenna can be arranged along the circumferential direction,the spatial position distribution provides the antenna with the condition of autonomous deflection of the radiation main beam.The beam switching of the conformal antenna can be realized by applying this characteristic.In addition,the beam switching mode in the circumferential direction is flexible,and it has the characteristics of large angle conversion and omnidirectional radiation.The large angle conversion property provides the basis of wide scanning range for conformal antenna.Although conical conformal antenna has the advantage of scanning in a wide range of circumferences,there are many limitations in achieving large-angle scanning,such as the low adjustable phase of phase shifter in the scanning process,the serious mutual restriction of two-dimensional array space radiation and so on,which restrict the scanning range of the antenna.Therefore,it is of great significance for the development of conical conformal antenna to study the method of broadening the scanning range of antenna.The work of this paper as follows:First.Research on wide solid angle beam switching technology for massive conical conformal array antennaA seven-element conformal linear array antenna(LAA)consisting of microstrip conformal elements with the structure of overlaping square patch(OSP)of ultra-thin slot-like antenna is proposed based on the pattern synthesis of linear arrays and circular arrays in this paper.Eight groups of LAAs form a massive CCAA with 56-element arrays distributed equidistantly along the circumference(Circumferential spacing equal 28°,?).The finite element method is emploied to calculate the conformal array antenna model,determine the beam switching mechanism by operating multi-output,and analysize the proximity coupling effects of the adjacent array.Multi-input and multi-output(MIMO)switch technology are applied to obtain the scanning of array beams.The designed CCAA works in 5G band,and the H-plane scanning angle can achieve 0-195 degrees.Secondly.Beam switching of multi-output feeding system controlled by radio frequency semiconductor switchA 56-channel feeding system based on radio frequency semiconductor switch(RFSS)and eight-channel power divider is proposed.By switching different feeding branches with on or off states of RFSS and integrating them with CCAA to link wireless information,wide solidangle beam switching of different LAAs is achieved,which greatly reduces the complexity of beam scanning feeding system design.Finally,the high-density interconnector(HDI)technology is used to obtain the fabrication and switching integration of the feed system and complete the fabrication of the whole prototype.The feasibility of wide solid angle beam switching technology for CCAA is verified based on frequency domain analysis and free space test method.The establishment of beam switching technology for conical conformal arrays can be of effective to broaden the scanning range and provides a wide application prospect for conformal antennas. |
PDF Full Text Request