confusion about vertical polarization and horizontal polarization

Discussion in 'Wireless & RF Design' started by donut, Jun 22, 2012.

  1. donut

    Thread Starter Member

    May 23, 2012
    Could you please help me to understand some basic concepts about antenna polarization. The books I have are really confusing and do not have examples that I can learn from. This is really frustrating because books are biased to people who have experience and not have any experience like me.

    Please look at the attached E plane radiation pattern image I attached (figure 13).

    The books image (figure 13) tells me that the attached image is a E plane radiation pattern which means that the E field is perpendicular to the earth (so vertically polarized).

    The books image (figure 13) tells me that the attached image dipole is located on the line from 90 degrees to 270 degrees.

    How can you have a vertically polarized antenna with a dipole positioned horizontally (90 degrees to 270 degrees)?

    What am I missing here? Im sure the book is accurate I just dont know how to read the radiation patter. Please help

    Figure 19 (attached) clearly correlates to horizontal polarized dipole but figure 13 says that it is a vertical polarized dipole.
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    Presumably 0° / 180° is the ground plane angle. So the dipole is offset from the ground plane by 90° and lies along the 90° / 270° axis perpendicular to the ground. Rotate the page by 90° and that should represent "reality" as you would perceive it standing on the ground and looking at the dipole.
  3. vk6zgo

    Active Member

    Jul 21, 2012
    Yes,you are confused!

    Fig 13 is ,if you could imagine it,looking down on a horizontally polarised

    In other words,the diagram is showing you the radiation pattern in azimuth ,not elevation.

    My understanding is that polarisation is not determined by the orientation of the E-field.
    If this is the book I think it is,this is covered earlier

    Actually,I was confused too,the E field orientation does determine the antenna's polarisation.
    I got E & H fields mixed up,but the other stuff in this posting is correct.

    Fig 19,in my opinion,not a very good diagram,simply shows that a vertically mounted dipole will have vertical polarisation,while a horizontally mounted dipole will have horizontal polarisation.

    Unless I miss my guess,the book is the ARRL Antenna Handbook.
    It's a great book,but it does have a fairly messy layout,so you may find diagrams that seem related,just happen to appear together,or the Fig referred to on one page may be on the next or previous page.
    The "Digest" type format,where a lot of the stuff is slightly modified articles from "QST" tends to lead to these problems.

    PS: Looking at the dipole diagram from "end on",the radiation pattern looks like a circle,instead of a figure 8,& looking at it from an angle,it looks like a doughnut.
    The following website has a PDF which includes (fig3.1) a graphical representation of this doughnut shape.
    Last edited: Aug 10, 2012

    Active Member

    Aug 8, 2011
    A "Quick & Dirty" way to look at the "Difference" between Vertical and Horizontal Polarization is to say that there is a 90 degree "PHASE" shift or "Differential" between the two.
    The above statement can open a large can of worms in many circles but like I said it's "QUICK & DIRTY".
    Something else you might want to do a bit of research on is "RADIO HORIZON" and I won't even get into that here.
    Another "Q&D", Vertical polarization tends to be "LINE OF SITE" for the most part (this is somewhat Frequency / Band Dependent and dependent on ionospheric conditions) , where "HORIZONTAL" polarization tends to follow the curvature of the earth's surface which tends to allow for greater range in distance.
    Another term you may want to do some research on is "DOPPLER SHIFT" .
    As "ZGO" pointed out earlier, the ARRL book's are good but can be quite confusing , you might do better looking for book's by William Orr or Walter Maxwell .