Research On High-precision Phased Array Antenna Receiver System

In recent decades,phased array systems have been a research hotspot in the field of antenna and microwave circuit,and are widely used in radar,communication,radio astronomy and other applications.With the progress of electronic component technology,phased array systems designed with various architectures based on analog,digital and hybrid technologies,have been developed rapidly.These architectures respectively have their own features in performance,complexity,flexibility,power consumption and cost.In this paper,a hybrid architecture of phased array antenna receiver syatem and its calibration method are demonstrated.It achieves the amplitude and phase control accuracy close to a digital array,and has a computing resources and power consumption similar to an analog array.The main contributions of this thesis are as follows.(1)An on-line calibration method of high precision image injection for phased array antenna is proposed.In view of the limitations of the existing calibration methods in the highprecision phased array receiving system,the internal calibration method uses the local oscillator port to inject the calibration reference signal,the calibration reference signal frequency as the mirror frequency of the operating signal,and the signal detection circuit of the system to detect the calibration reference signal,in order to obtain the phase and amplitude error of the phased array systems.The internal calibration method in this paper does not need additional calibration signal injection circuit,and the circuit complexity of the calibration signal transmitter is low,so it can be directly integrated into the array local oscillator.This not only reduces the complexity of the circuit and the cost of the software and hardware of the calibration,but also facilitates the calibration efficiency greatly due to the simultaneous error detection and calibration process.The validity and accuracy of the calibration method in this paper are verified by the statistical analysis of thousands of measured results.The internal calibration method solves the technical problems of low efficiency in large-scale array calibration and difficulties in on-line real-time calibration of system phase and amplitude errors.(2)An even-mode excited substrate integrated coaxial line(EME-SICL)is proposed and inveatigated.Compared to conventional SICL,the EME-SICL features low loss,low dipersion and low distortion.The EME-SICL has been applied to the high-precision phased array antenna receiving system.A bridger between an EME-SICL to a surface transmission line is proposed,which is used the connections among models in the phased array antenna receiving system.(3)An X-band high-precision phased array antenna receiving system with 16 channels is designed and implemented.The system uses an architecture of hybrid beamforming,and it can produce multiple beams simultaneously.high-precision local oscillator phase-shifting method based on DDS is adopted for array phase control,which has the beam control accuracy close to that of digital phased array.This architecture not only improves the beam control accuracy and stability of the phased array receiving system greatly,but also provides a wide signal bandwidth and at the same time has a relatively low software and hardware cost.This array validates the high-precision and low-cost phased array receiving system architecture,and completes the hardware and software design including antenna array,multi-channel phased local oscillators,multi-channel RF front-end,main board and control circuits.The automatic test system is designed and constructed.The image injection real-time internal calibration method is used to calibrate the hybrid receiving array and investigate the beam forming performance,which verifies its the high-precision amplitude and phase control ability.The experimental results show that the array has a phase control accuracy better than 0.5°and a beam direction accuracy better than 0.25°.The designed system can achieve a beam scanning range of more than+/-45°,a low sidelobe beam with sidelobe level lower than – 25 d B and a difference beam with zero depth better than – 40 d B.In this paper,the key technical problems of the design,on-line calibration of the phased array receiving system are solved,and the corresponding RF microwave circuits of the highperformance array system is designed.It can be applied to phased array systems of various scales and architectures for various applications.