Research On Digital Array Antenna Measurement Technology

With the rapid development of radio frequency integrated circuit technology and digital signal processing technology, digital array antenna (DAA) system has attracted increasing attention and hence wide researches on it. Compared to phased array antenna system, digital array antenna system integrates digital beamforming (DBF) unit and digital signal processing unit, which brings it with many advantages over other normal antenna systems, such as high gain, low sidelobe, multi-beam scanning, multiple target processing and adaptive beam control. Performance index measurement of digital array antenna is the important segment of system development process.The antenna elements, RF channels, A/D converters and the integrated connection of preprocessing circuits in the integrated DAA discussed in this article do not include a RF interface which can be connected directly, and hence cannot be measured by conventional antenna measurement system to measure the antenna performance. This article proposes a digital domain parameter measurement scheme, which solves the antenna parameter measurement problem based on DBF.Firstly, the composition and character of digital array antenna system is given in this thesis. Then theoretical analysis of difference bewteen performance index measurement of traditional antenna and DAA is given, the researches are conducted in this thesis about the measuring method of digital array antenna parameters including antenna pattern, system G/T value, EIRP value, beam-shaping, and etc.Secondly, automatic measurement software of digital array antenna system based on MFC is programmed. The program mainly covers completing real-time communication between personal computer and turntable motors through serial port, achieving remote control of Agilent signal generator and spectrum analyzer by personal computers via local area network, realizing real-time data interaction between personal computer and DSP module on digital beamforming printed circuit board using local area network. Then the pattern of the antenna is drawn using multithreading technology and TeeChart Pro ActiveX.Finally, an actual far-field measurement of digital array antenna system with 960 elements is performed. The analysis of test results is performed to verify the feasibility and validity of the measuring method and analyze the factors that may cause measurement errors. The test results show that the developed digital array antenna meet the requirements of system performance index.