Research On Grating Lobe Suppression Of Large-spacing Arrays Based On Pattern Reconfigurable Technique

Large-spacing arrays reduce the number of active elements under the same aperture by increasing the element spacing(usually more than half a wavelength),thus saving the number of transceiver components(T/R components)connected to the beam scanning array,and becoming one of the key solutions to reduce the cost on beam scanning arrays.The advantages and disadvantages of large-spacing arrays coexist,among which the advantages include lighter weight,thinner volume,lower manufacturing costs,better heat dissipation,and less energy consumption.Its biggest drawback is that grating lobes inevitably occur during scanning.Therefore this thesis studies the grating lobe suppression of large spacing arrays based on pattern reconfigurable technique.The main contents of this thesis are as follows:In chapter 1,providing a brief overview of the research context and practical significance of large-spacing array,while also highlighting their primary limitation: the occurrence of scanning grating lobes.To address this challenge,both domestic and foreign researches have been dedicated to developing techniques for suppressing grating lobes of large-spacing array.Existing techniques have been evaluated and compared with their respective strengths and weaknesses identified.Based on the above research and analysis,this thesis has conducted research on grating lobe suppression of large spacing arrays based on pattern reconfigurable technique.At the end of this chapter,the innovations and content structure arrangement of this thesis are described.In chapter 2,the beam scanning principle of two-dimensional beam scanning array is summarized firstly.Secondly,a beam scanning array model with pattern reconfigurable subarray as the basic element is constructed,and the radiation pattern formula of the subarray is derived.The position formula of nulls and grating lobes in the subarray pattern are obtained,and the influence of key parameters to the position and amplitude of the nulls is studied.Finally,according to the above theory,a large-spacing grating lobes suppression scheme based on the subarray pattern null reconfigurable technique is designed.In chapter 3,a beam scanning array of one wavelength spacing operating in S-C band with 40% impedance bandwidth is designed as the theoretical verification model of this thesis.And PIN diodes based switch transmission line phase shifter is designed for the discrete adjustable nulls of the subarray.Finally,the integrated full wave simulation results show that the array can achieve ±30° scanning without grating lobes in the plane with large spacing.In chapter 4,a beam scanning array of one wavelength spacing operating in X band with 10% impedance bandwidth is designed as the theoretical verification model of this thesis.And varactor diodes based reflective phase shifter is designed for the continuous adjustable nulls of the subarray.Finally,the measured and simulated results show that the array can achieve ±50° scanning without grating lobes in the plane with large spacing.Compared to the previous chapter,the scanning angle of the array is further broadened under the condition of larger spacing.In chapter 5,summarizing all the work of this thesis and prospects for the next step.