Wideband Polarization Programmable Antenna And Array Research

With the increasing complexity of communication environment and the demand of channel capacity enhancement,polarized reconfigurable antennas and arrays are of great value in communication anti-jamming,reducing multipath effect,lowering transmission loss and improving signal transmission stability because of their ability to exploit the freedom of antenna polarization.This thesis is mainly divided into two parts: antenna cell design and algorithm study.In the unit design part,a low-profile broadband multi-line polarization reconfigurable antenna unit,an ultra-wideband polarization programmable antenna operating in X-band,and an ultra-wideband antenna operating in S-band are designed.For the array,based on the ultra-wideband multi-linear polarization reconfigurable antenna array,combined with the antenna polarization state selection algorithm and vector beam formation algorithm,the broadband large-angle scanning beam with continuously polarization adjustable can be realized under the premise of one antenna corresponding to one RF channel.The main contents of this paper include:1.A low-profile,broadband,multi-line polarization reconfigurable antenna has been designed.The antenna is capable of switching among seven different linear polarization states,and by loading a rotationally symmetric artificial magnetic conductor(AMC)structure,the overall profile is reduced by a factor of three compared to a metal reflectorloaded antenna while ensuring the same radiation performance in all linear polarization states.2.An ultra-wideband multi-linear polarization programmable antenna operating in X-band has been designed.By carefully designing the shape of the printed dipole in the radiation layer,multiple polarization state switching and ultra-broadband impedance bandwidth are achieved simultaneously.By integrating the antenna with the designed board,the polarization of the antenna is programmable through FPGA control.The small lateral size of the antenna and the design of a small,low-cost DC control circuit make the antenna suitable for denser spaced group arrays and maintain good performance.To demonstrate this,the antenna is placed in a conformal platform array environment and the design is verified by processing tests.3.An ultra-wideband polarization programmable spherical crown array was designed.Based on the proposed seven-linear polarization reconfigurable antenna array,a continuously variable linear polarization and circular polarization beam synthesis can be achieved by selecting discrete polarization states of each array element with reasonable phase configuration.Firstly,the correctness of the algorithm is verified by the 19-element spherical conformal array,and then the wideband arbitrary linear \ circular polarization synthesis with large angle scan is realized by the 179-element spherical conformal array.The multi-line polarization reconfigurable antenna array overcomes the gain synthesis loss and cross-polarization increase caused by the different orientation of the array elements,and can have higher gain and lower cross-polarization level in the main beam when scanning at large angles.