Time-domain three antenna method for evaluation of antenna factors of log-periodic antenna

摘要

we have proposed the method for evaluating the free space antenna factor of a log-periodic broadband antenna (LPDA) with time-domain technique [1]. Our method is based on the techniques of time domain analysis and pulse compression technology. The introduced function enables us to isolate the direct wave from the reflected waves on the ground plane in an open area test site for free-space antenna factor evaluation. In our previous method, LPDAs are held 4m high on the masts and with 10m distance between them. The antenna separation is 10m and the reflection path slightly longer. It is difficult to separate these two waves by a simple time-gate and pulse compression technique by using direct wave of lm antenna separation. In this paper, LPDAs are held 6m high on the masts and with 10m distance between them. Then, to calculate the direct wave by using the Wiener filter that is expressed by the frequency domain direct wave of 3m antenna separation. Our proposed method can completely separate the direct wave from the measurement waves on the ground plane in an open area test site.