Research On Active Phased Array Receiver Based On Local Oscillator Phase Shifter

With the development of wireless communication,the antenna technology is constantly innovating as the result of high requirements for transmission signals.Phased array antennas are widely used in radar systems because of their beam flexibility,adaptive mode and the ability of simultaneously monitoring and tracking targets.And among them,the active phased array has more advantages and better development prospect than the passive phased array because of its small loss and high stability.The design of the phase shifter in the transceiver assembly is the key to the entire active phased array research.Based on the local oscillator phase shifting technology,a 16-channel active phased array receiver operating in the satellite frequency range of 11.7-12.75 GHz is designed.A phase-shifting scheme of local oscillator is determined after comparative analysis of various phase shifting techniques applied to phased arrays.The proposed combination of digital frequency synthesis(DDS)and phase-locked loop(PLL)produces a phase response with high phase resolution and low spurious local oscillator.The phased array receiver is designed with low noise amplifier,filter and other modules.The TFF1014 chip provided by NXP is used in the design process for PLL and mixing functions,which greatly simplifies the circuit design and reduces the receiver's dimension.In addition,since four AD9959 chips are used to provide the DDS output signal,the synchronous operation of the DDS chips is completed by the combination of the XOR gate and the manual software synchronization mode provided by the chip.After the circuit design is completed,the actual receiver board is tested and calibrated.It is found that the system has good spectral characteristics in the required intermediate frequency band of 1.1-2.15 GHz.Considering the influence of noise contained in the output signal,a way of least squares method for phase calibration is proposed.In this way,a simple and accurate phase calibration for 16-channel active phased array receiver is completed.