Planar Near Field Measurement Of Antenna In Time Domain And Software Design

Along with the rapid development of broad band technology of modern communication and radar technology, short pulse antenna and ultra-wide bandwidth antenna have been wide used. That means a higher requirement for antenna measurement technology. The traditional antenna measurement system in frequency domain can only be used to measure the finite bandwidth. It is inefficient to the measurement of ultra-wide bandwidth antenna. That is why we need to extend our measurement from frequency domain to time domain. Since the theory of near field antenna measurement in time domain was brought forward by Rome laboratory in U.S.A in 1994, many researchers throughout the world have attached importance to it.Firstly this paper has introduced the background of antenna near field measurement technology. After that we have analyzed the core theory of the technology of near field measurement in time domain: near-field far-field transformation. As a scale to measure precision and reliability, error analysis plays a very significant role in near field measurement in time domain. This paper has studied how to use Time-gate theory to remove the effect of reflect between antenna and probe and provided the method of setting time-gate. Such topics as the error caused by the probe, the transformation of near-field to far-field when the probe-corrected is considered have also been researched. Moreover, the possibility of using wide angle conical antenna as time domain probe has been broughtforward and the feasibility has been proved theoretically.The concept of Virtual Instruments brought about a revolution in the area of measurement. As a requisite part of virtual instruments, LabVIEW provides a very good program development environment. It was designed especially considering the needs of engineers and scientists. With strong performances, LabVIEW enables its users to connect all kinds of hardware and software products very conveniently. This paper has successfully combined the near field measurement technology in time domain with the virtual instrument and use LabVIEW to perform the data collections and processing. In this paper we have mainly researched and designed the data processing part of the software and proved its correction. Due to the nature of its excellent extendibility, LabVIEW ensures the integrity of the software and the completion of the whole system.At the end of the paper, we have summarized the research of the near field antenna measurement in time domain and made suggestions for the next step of the work.