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H-Plane and E-Plane

C2

Sr. Member
Aug 3, 2005
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I'm looking at antenna radiation plots and am seeing the octopus image for both E- and H-planes.

I thought one plane was vertical, and that I would not understand the use for when discussing horizontally polarized Yagis, but if it were plotted I would expect more of an omni pattern. So what is the difference in these planes and if they are just H/V plots, is that also common to how the antenna is polarized? I don't get it otherwise.
 

RF is an electromagnetic wave. It contains an electrical component as well as a magnetic component. When we speak of an antennas polarization we are speaking of how the electrical component is oriented. This is the E-plane. The H-plane is the magnetic component and is at a right angle to the electrical component. With a vertical antenna the electric field (E-plane) is vertical and the magnetic component (H-plane) is horizontal with reference to the earth. With a horizontal antenna the electric component (E-plane) is horizontal and the magnetic component (H-plane) is vertical with reference to the earth.


http://en.wikipedia.org/wiki/E-plane_and_H-plane
 
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OK, so most antenna radiation plots show just one plot. Which one is most common? for example: http://www.telewave.com/pdf/TWDS-7041.pdf

That link shows both the E-plane and the H-plane plots however it is odd that they rotated the H-plane plot by 90 degrees. The E-plane has the 0 degree point at the top and the H-plane plot has it at the far right. It would have made comparisons less confusing if they had plotted them the same. Anyway to answer your question we are generally concerned with the E-plane plots. You can indeed make antennas that function as magnetic and not as electric as in a very short magnetic loop antenna however unless the antenna is specifically designed as a mag antenna then we are concerned with the electric field which is the E-plane.
 
Ok, we are going to publish both plots. One of the engineers here liked that orientation, but it sure confused me at first. Some of our other reference data is plotted on a linear scale too. It's frustrating how inconsistent the data is. Most of the published data I've seen though just had H-plane plots. Thanks.
 
I still had one question. The "linear" data we have is gain data. I can plot this in Excel, but the scale is not the same as in the sample above, which looks like a log scale or is "compressed". I need to transform the data so it plots correctly. Any idea of the transform?
 
So the plot I'm trying to duplicate is in the PDF above (http://www.telewave.com/pdf/TWDS-7041.pdf). Someone suggested that is from an ARRL application, maybe a software component of the collection supplied with the handbook?

Otherwise, plotting on a log scale does not work because the numbers are negative. Any advise on how to create that plot or translate the linear polar data so it will overlay on a log polar scale? Thanks!
 
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I'm not sure I'm completely following the last question. The plotting on most models shows the "gain rings" as negative numbers, which indicates the amount of reduced gain on that point of the plot as compared to the max gain of the overall pattern (did what I just typed make any sense?) Are you looking for a model that shows the "rings" as dBi gain instead?
 
So the plot I'm trying to duplicate is in the PDF above (http://www.telewave.com/pdf/TWDS-7041.pdf). Someone suggested that is from an ARRL application, maybe a software component of the collection supplied with the handbook?

Otherwise, plotting on a log scale does not work because the numbers are negative. Any advise on how to create that plot or translate the linear polar data so it will overlay on a log polar scale? Thanks!

I'm not sure I'm completely following the last question. The plotting on most models shows the "gain rings" as negative numbers, which indicates the amount of reduced gain on that point of the plot as compared to the max gain of the overall pattern (did what I just typed make any sense?) Are you looking for a model that shows the "rings" as dBi gain instead?


Sorry about the delay answering here. Father-in-law passed away last Friday so I have not been here much....anyway Moleculo has the answer above. The plot is always referenced as to maximum gain which is called zero dB which is placed on the outer ring. Anything else is expressed as a negative number since it is always less than maximum. Polar plots do not really express gain as that is simply stated as an absolute number such as 10dB. In this case you use the polar plots to see the overall pattern shape and what gain the antenna has at any bearing off from directly forward as referenced to the maximum gain. Polar plots are never about actual gain but rather about the gain as referenced to maximum.
 
Captain, sorry to hear of the father in-law.

All of the numbers I have are in dBi at angular increments. I understand how to normalize that data set (to get 0 dBi on outer ring).

I am wondering what is the industry standard/correct scale for these kinds of plots (which I assume is shown in my example)? Is that log polar? Excel will happily plot all my data on a linear polar scale, and I get the appropriate looking plot, but it is not on the same scale as the other, so an apples to apples visual comparison cannot be made.

Normally, in Excel one would just tick the Log scale option, but naturally Excel will not like the log of a negative number. So I've tried all kinds of mathematical transforms of the data and cannot produce the correct plot. Someone also told me that the scale is not a log polar scale anyway, it is compressed or something (like a compressed Smith chart).

I also run into issues when setting scale range. The center of the circle is what value? Theoretically infinity? Or some finite value, like -60 dBi? Changing that also changes the plot slightly.

Someone that mentioned the compressed scale said the mfg is just doing that to suppress the side lobes and emphasize the main lobe.
 
I don't know if there is an industry standard for these plots, but I would tend to doubt it. Check out the wikipedia page on antenna measurement: about 1/2 way down they show examples of the same antenna plotted four different ways: http://en.wikipedia.org/wiki/Antenna_measurement

Imagine how useful the differences could be for marketing purposes.
 
All of the plots on wiki look linear to me. If you mess with the scale then you can make the pattern look almost like anything. You're supposed to be able to use the plot to figure out the half power beam width.
 
so what is this freakin scale? ARRL has this scale but nobody talks about it.

All I can figure out so far is that the data points of x must plot as x'

My normalized gain data x is plotted as x':

0 dBi is plotted as 0 dBi
-8 dBi is plotted as -3 dbi
-22 dBi is plotted as -10 dBi
-34 dBi is plotted as -20 dBi
-41 dBi is plotted as -30 dBi
-45 dBi is plotted as -40 dBi
-50 dBi is plotted as -50 dBi

f(x)=?

I want to put the plot on the right onto the graph scale on the left, and am wondering what is the math transform to get there. Obviously I cannot just drop the plot on the scale as I have. The plot on the right is from Excel. I'm needing to transform the data in Excel to get the proper plot shape so when it's overlaid on the proper scale the plot is correct.

(PS, I know the scale in Excel will not be correct, and I know the plot is rotated 90* right now.)
 

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I fed some data right out of the ARRL antenna handbook (the section that discusses the "ARRL Log Coordinate System" in extreme brevity) to one of our world class engineers. He said it made no sense for the various reasons he stated. But, now knowing what we are looking for, we discovered the transform:

0.89^(-dB/2)

Excel makes very nice plots, but will not produce the proper scale so the plot needs to be overlaid on the proper scale.

Yeah!
 

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