Research On Beampattern Optimization Method Of Frequency Diverse Arc Array

Compared to traditional Frequency Diverse Array(FDA)antennas,the Frequency Diverse Arc Array(FDAA)design found that the curved array structure and a small frequency offset between the array elements were used to obtain beampattern related to range,angle,and time,and to realize 360° omnidirectional scanning.Thus,its application prospects in modern radar and communication systems are greatly improved.Due to the great difference between linear array and arc-shaped array in geometric structure,the array model,range-angle decoupling,dot-shaped beam synthesis and optimization of frequency diverse arc array are studied and analyzed in this paper.The main work and innovation of this paper include the following aspects:1.Aiming at the problem of range-angle coupling existing in curved frequency array beampattern,the method of solving range-angle coupling in curved frequency array is studied by means of symmetrical non-uniform frequency bias,and the application of symmetric logarithmic frequency bias based on different base numbers,symmetric trigonometric function frequency bias and symmetric cone window function frequency offset in curved frequency array is compared and analyzed.The simulation results show that the problem of range-angle coupling can be effectively solved by symmetrical and non-uniform frequency offset equalization.2.In order to solve the problem of limited scanning angle of traditional linear array frequency diverse array beam,the element selection,phase compensation and frequency offset design of frequency diverse arc array are studied,and the dot-shaped beam pattern synthesis of frequency diverse arc array based on equivalent linear array and virtual array is proposed.The equivalent linear array method projects the frequency diverse arc array onto the equal phase plane to carry out phase compensation and frequency offset design,while the virtual array method realizes phase compensation and frequency offset design by constructing virtual array.The simulation results of the pattern show that the two methods can obtain the dot-shaped beam of 360° omnidirectional scanning.3.Aiming at the high sidelobe near the main lobe of the beampattern due to the inverse density weighting phenomenon of the frequency diverse arc array,a beam optimization method for sidelobe suppression of the arc-shaped frequency array was studied,and a symmetrical non-uniform frequency bias and amplitude weighted beam optimization method based on the arc-shaped structure was proposed.The method suppressed the sidelobe energy through frequency bias optimization design and array amplitude windowing processing.Simulation results show the effectiveness of the proposed method.