[MLB-WIRELESS] FW: Re: waveguide antenna

[drew at no6.com]

Update on the optimum waveguide coming, and some simulated plots of the e3 design attached... text from Trevor Marshall below:
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Drew,
I am getting close to publishing an optimum design.

I simulated the radiation patterns of the antenna you pointed me to (below)
and this simulation shows a sub-standard design having a fair bit of time
domain reflection.

I measured the parameters from the photos he had put on the web. I assumed
a 0.25 inch slot width and a 0.75 inch center to center spacing of the
slots. I assumed he had calculated the lengths correctly.

Attached are the two patterns. You may circulate them around as long as you
reference that they came from me and disclaim that I do not have his exact
dimensions (I bet I am pretty close...)

Peak gain is computed at 14dbi, (assuming he is feeding it correctly),
terrible front to back ratio (of course). Only 3 dB more forward gain for a
much higher vertical directivity than the simple BiQuad
(http://TrevorMarshall.com/biquad.htm )

.Trevor. Marshall...
Contributing Editor, BYTE.com


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