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Thread: Antenna Simulation - Information source

  1. #1
    Michael Mictronics's Avatar
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    Lightbulb Antenna Simulation - Information source

    Just started this thread for those who are (like me) interested in antenna simulation.

    Would be nice to build up a knowledge base for such simulations, optimization of existing and new designs, theoretical verification of design parameters etc.

    Some PC tools for simulation:
    * 4nec2 (free)
    * HFSS
    * CST Microwave Design Studio
    * Antenna Magus

    My favorite is CST for now, very powerful and, if setup properly, results will be close to reality. Though needs time to get used to it.

    While setting up a model in CST I try to use as much parameters and math as possible so later on optimization can be done automatically.

    I going to list some of my setups here from time to time.

    The Skew-Planar-Wheel:
    Click image for larger version. 

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    The results shown on the picture are no tweaked, dimensions are just set for best return loss.

  2. #2
    KB3WHA kenkos68's Avatar
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    I was hoping a thread like this would show up!

    I have been playing with 4nec2 at home and at work. How close is 4nec2 simulations to actual? I ran OMM's CP open biquad NEC (RHCP) and got the best return loss at 1300 Mhz. Yet OMM shows it right on 1280 Mhz from his analyzer. If I add 0.5mm to section 'A', I get the best simulation return loss at 1280 Mhz where I want it. If I were to build this, which dimensions should I use? I ask because I don't have access to test equipment yet to verify.

    I have also scaled down OMM's pinwheel to 5800 Mhz. I have built these and they do work well, but again, no equipment to verify where it really is.

    Math isn't a problem for me. What I am teaching myself now is more antenna theory.

    -Ken

  3. #3
    Michael Mictronics's Avatar
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    Ken, since you have no test equipment I recommend to take the practical proofed values from OMM.

  4. #4
    Subscribed. This guy is not an Antenna Magus, he is an Antenna Genius.

  5. #5
    Engineer for Jesus Christ IBCrazy's Avatar
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    One thing that I find very beneficial is the X/R frequency sweep analysis, not the return loss plots. The return loss only tells part of the picture. Analysis of the X/R graph has helped me design entirely new antennas. The turnstile, crosshair, and the pentalobe sphere antennas were all designed using the X/R frequency sweep as the development tool. I am working on another CP BiQuad right now using this.

    Try this one: take 2 skew wheels set to 100 ohms at 1240 or 1280 MHz. This translates to: 1 at 1160MHz, the other at 1360MHz (roughly guessing here). Place them 1/2 wavelength apart with one flipped upside down underneath the other and feed them with exactly 1 wavelength of coaxial cable in a "T" connector. Now do a frequency sweep of this antenna at 1200-1320MHz. Plot the graph of this new antenna. Now change the spacin between the two antennas and watch what happens

    Send me your Email address or just Email me. I will send you the source code for the Pentalobe sphere and the Crosshair antennas I have developed. I think you will really like them. Just don't share the details until I'm ready to release.

    -Alex
    If it is broken, fix it. if it isn't broken, I'll soon fix that.

    videoaerialsystems.com - Performance video piloting

  6. #6
    Michael Mictronics's Avatar
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    I have setup a new antenna simulation for a so called tri-filar helical antenna.
    The design is based on the following US patent: http://www.freepatentsonline.com/6738026.pdf
    Unfortunately there are still some unknown factor I can't solve from the patent:


    • There shall be a ground plane below the monopole structure, what size?
    • Does the monopole lower end needs to be connected to ground?
    • What material can be used for the dielectric?

    Any ideas?

    There seems to be also a IEEE article about this antenna: http://ieeexplore.ieee.org/xpl/freea...number=1220046
    Is someone with IEEE access here who can may provide a copy to me?

    My full parameterized model:
    Click image for larger version. 

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  7. #7

    A rare gem, an iOS-based Array Analzyer

    There had been a lot of developments from 2012 to present day in 2019. For the average Joe, CP antennae had come to the point that one could pick up a brand-less "make" of the open-source pagoda on Aliexpress for less than 10usd, and it would perform close to if not equilvalent to an old immersionRC clover or a recent VAS Ion from reputable sources that cost twice as much. As such, most people would rather buy than make their own antennas for FPV. On the bright side of this hobby, test equipments for 5.8ghz antennas (or arrays) are becoming affordable, we could look at options such as a 100usd Arduino-based SWR meter by OwlRC within the Hobbyist range to a 2000usd KC901v VNA at the low-end of the Professional range.
    Recently, I happened to find this old iOS Antenna Array Analyzer in the iTunes folder on my old computer. Mind you, it is by no means a PCB/microwave simulation software like CST or Altium nor is it an antenna modeler like 4NEC2. What it does best, is the simulation of 3D radiation pattern for elements in an array formation. The elements it supports are basic antenna-types like patches and dipoles. Despite the simplicity, I found it particularly useful when working on the layout of multiple microstrip antennas on a PCB For anyone who is viewing this old thread and still building antennas, you could download the iOS-based Array Analyzer from the link provided in the video's description and drop your comments, likes or dislikes.



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    Last edited by RC-Concepts; 26th March 2019 at 03:54 AM.

  8. #8
    http://www.youtube.com/watch?v=p8i82IXBN5I

    Here’s an antenna plotter I came up with, for now it is not scaled to gain in DB, but it plots the actual beam width in real world space. Feel free to edit the source codes (Python).

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