Hardware Design For RF Front-end Of Active Phased Array

In the development of phased array radar,active phased array technology has become an important direction by virtue of its advantages of high reliability,long operating distance and bottom sidelobe.By controlling the phase and amplitude of signals in each antenna element of the phased array,the transmitting direction of the whole synthetic beam can be controlled.An active phased array is characterized by T/R components connected behind the antenna transceiver unit,which enables each channel of the phased array to receive and transmit electromagnetic waves independently.The research and design of this subject mainly covers the hardware circuit design of RF front end of active phased array and the program design of FPGA as controller.In the design,T/R module was designed into four transceiver channel modules according to the requirements of the subject and the actual installation space,with functions such as power amplification,receiving filter amplification,channel calibration,analog phase-shift attenuation,equipment selfinspection.FPGA is used to realize the beam control of equipment,which is controlled by the superior task system.The phase control code is calculated in real time according to the communication requirements,and the phase distribution is fast and accurate according to the phase stored in advance.Previous active phased array of RF front-end channel amplitued-phase consistency usually rely on manual testing compensation.In this project,a calibration module is added to the design of the front end of the phased array to check the phase difference of each channel in real time by means of automatic monitoring and upper computer control,which to achieve accurate regulation of the phase,amplitude and frequency of the beam and improve the reliability of the equipment.This article first introduces the characteristics and development trend of active phased array technology,describes the research status and research contents,and then analyzes the system structure and working principle of each module,then the hardware design and software implementation are described and some functions are tested,the final test results show that this design meet the system requirements.