Research On The RF Front-end And Antenna Array Configuration For Square Kilometer Arrays

With the rapid development of deep space exploration,the requirements for observation array are increasingly high.Square Kilometer Array(SKA)is the largest and most sensitive aperture synthesis radio telescope jointly planned by international astronomical community.The SKA baseline is as long as hundreds of kilometers and the number of array elements is millions,which leads to high demands on the antenna unit and array configuration.In this paper,SKA is taken as the application background,the receiving RF front-end is deeply studied,and relevant design and research are carried out.The antenna and front-end filter applied to SKA are designed,and an optimization algorithm is put forward to improve the array configuration and beam scanning of SKA sub-station.The main research contents are as follows:(1)A high-gain,ultra-wideband antipodal Vivaldi antenna is designed for the operating frequency of SKA low-frequency and mid-frequency array.In order to improve the performance of the antenna at low frequency,a method of loading periodic oblique slots edge on the radiation arm is proposed,which expands the antenna bandwidth,improves the S parameters and pattern,ensuring that the antenna can operate in the frequency range of 0.3GHz~13GHz.(2)In views of the characteristics of SKA array multiple interference signal and large array size at low frequency,a new type of self-rolled-up interdigital capacitors is proposed by using planar semiconductor processing compatible materials and fabrication methods,which transforms the planar interdigital capacitor in the traditional sense into a 3D structure,greatly increasing the capacitance density and improving the space utilization rate.In addition,a highly integrated on-chip LC filter is designed,which can be integrated with the SKA antenna output port in the future to form a miniaturized receiving front end.(3)Based on the background of SKA low frequency aperture array(LFAA)application,the configuration of 16 unit antennas in a single Tile is studied,and the configuration of 256 element antennas in a single station is improved by particle swarm optimization.In this way,the target of low sidelobe and without grating lobe is successfully achieved by optimizing iteration,and ±45 degree phase scanning is realized in the frequency range of 50~675MHz.