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Can the TDR option on a VNA be useful for developing narrow band antennas?

Question asked by drkirkby on Jan 10, 2013
Latest reply on Jan 10, 2013 by daras
The subject of modeling and testing Yagi-Uda (or as most people call them Yagi) antennas is a very common topic on amateur radio mailing lists. These are narrow band, with a bandwidth usually of 1-2% of the centre frequency. 

I then had the idea of whether the TDR option of a VNA could tell one anything useful about such an antenna.   A quick check of IEEE journals showed I was not the first person to think of using the TDR option of a VNA for antenna characterisation, but the papers I found were all on wide-band antennas, not narrow band ones like the Yagi-Uda. 

I decided to post this idea on the moon-net mailing list - for amateur interested in earth-moon-earth communications. 

One ham wrote this was the most thought-provoking idea he had seen in ages, yet another (Leif, SM5BZ), who is one of the brightest hams in the world, thought this would not work, as the radiation pattern of an Yagi changes rapidly with frequency. 

Then looking at some of the Agilent's papers, and the title of Joel's Ph.D, suggested the TDR function has been useful on narrow band filters, so once again it got me thinking about the narrorw band antennas. 

Anway, I'd appreciate the thoughts on the gurus on here.  

BTW Joel, if you read this, are you from the UK like myself? I found a reference to your Ph.D, which was done at Leeds university, so I wondered if you were from here. 

Dave, G8WRB.  

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