Mathematical Techniques for Near Field Radiation Pattern Characterization of Digital Arrays

Digital arrays present unique challenges to characterization. This is mainly a result of the output of digital arrays being a digital, rather than analog, signal. Traditional techniques for characterizing analog systems must be modified to allow for the assessment of antenna systems with integrated analog to digital converters, such as the Xilinx RF System on Chip (RFSoC). In particular, it is necessary to format and post process data generated by the RFSoC to determine the far field spectrum, radiation pattern, and near field hologram for the digital array. This paper will show how these formatting and post processing techniques can be applied to characterize a digital array based on RFSoC technology. A test bed digital array was created and characterized using a modified analog near field range measurement system, as has been described in previous work. Additionally, data generated by the RFSoC has been formatted and prepared in such as way as to allow for ease of calibration and post processing. It is shown that this post processing technique produces good results when compared with a representative traditional analog measurement.