Design Of IF Control Module For Near-field Antenna Measurement System

In the development of the modern radar antenna,the antenna measurement is an important means to quickly measure the parameters of the antenna and verify whether the performance of the antenna meet the requirements.The near-field antenna measurement technology has gradually become the most common antenna measurement means because of its small space,easy to implement,high precision,automation and other characteristics.In this thesis,an IF control module of the near-field antenna measurement system is designed by analyzing the parts of the near-field antenna measurement,such as RF signal sources,signal conditioning and acquisition,command control and data transmission.The module includes the hardware design and the software design.The hardware design of the control module includes the following four functional parts: The first one is the command parsing module,which mainly analyzes commands sent by the control software,and then loads the functional instructions into each command register of the control module.The second one is the IF channel control module,which mainly controls the program-controlled amplifier,ADC conversion correction,clock chip,delay chip and resolution bandwidth(RBW),in order to obtain good quantitative calculation data for the near-field amplitude-phase measurement.The third one is the RF sources control module,which mainly completes the control of the excitation/local oscillator sources,such as frequency,power,dwell time and other parameters,and completes the control of the work mode,such as trigger mode,frequency hopping mode;The fourth one is the data upload control module,which mainly completes the design of the data transmission channel based on the Ethernet protocol,and the design of the measurement data upload mode(direct mode and cache mode).The software work of the control module includes the design of the control functions for each function module of the hardware,and the design of the program for data reception and processing.The design work of the control functions includes the control command of each function part of the instrument,design of the parameter definition,and design of the control function library.The function of the data reception and processing includes reading the amplitude and phase data and the IQ data,and thencalculating and showing the amplitude ratio and the phase difference and spectrum of the baseband signal.Through the tests of the functional modules and the experiment with the antenna scanning frame,the thesis verifies the validation of the design scheme,and the performance of the control module has reached the expectations.