1

I have an antenna which runs at 917MHz located inside a metal structure that measures in at 6m long, 2m wide and 1.9m high. The exact location of this antenna will be in the center against the length of the metal structure. I would like to know how do I mathematically predict the behavior of the EM waves emitted from the antenna at any given point inside the container, without the use of any simulation software?

My objective is to determine the effect of enclosing an antenna inside a metal structure to illustrate the effects of super positioning mathematically not the entire process but just a few iterations to see and understand how the you can achieve the same goal as the simulations.

I feel like all I know is to fill in the parameters in the software and click run simulations but without fully understanding whats going on in the background. And sadly this is not a good way to grow academically.

This is purely for my own understanding not for any project or deadline. If anyone wants to criticize me for not using simulations, please refrain from commenting has I have mentioned my reasons or if you think this is stupid and a waste of time.

JoeyB
  • 1,804
  • 13
  • 34
  • Why do you want to use analysis methods of the last century and not do a simulation? – Ken Grimes Jan 31 '20 at 20:33
  • You want to analyze the efficacy of a Poorly defined Faraday cage with 1/4 wave resonant points and 1/2 wave slot leakages with stubs at rusty for what reason? To prove you don’t know how EMI leakage works with RF? And no specs !! – Tony Stewart EE75 Jan 31 '20 at 20:39
  • @KenGrimes this is not for a project, it is for my own understanding. I have no understanding of the mathematics involved behind these simulations and would therefore for my own understanding like to know how these things work but without the shortcuts of filling in my parameters and clicking run simulations. – JoeyB Jan 31 '20 at 20:55
  • @TonyStewartSunnyskyguyEE75 my apologies I will edit. – JoeyB Jan 31 '20 at 20:56
  • How fast can you solve Maxwell's equations, for several thousand points within your volume, iteratively until your results converge (that is, don't change very much between iterations)? Because that's what you're looking at for the problem you descrcibed. – SteveSh Jan 31 '20 at 21:26
  • We’d run out of letters of all the known alphabets in the world trying to use formulas. Take a break and think about what you’re asking. – Andy aka Jan 31 '20 at 21:53
  • @Andyaka I see my question is misleading. I have updated it. I want to know how I can mathematically reach the same goal as the simulations but for a few iterations. Because I dont know how to even do it mathematically. Again not the entire iterations but just a few. – JoeyB Jan 31 '20 at 21:58
  • @user287001 I see my question is misleading. I have updated it. I want to know how I can mathematically reach the same goal as the simulations but for a few iterations. Because I dont know how to even do it mathematically. Again not the entire iterations but just a few, the videos on youtube just explain the theory but dont show how its is actually done fully and I feel like I am cheating because I dont fully understand it. – JoeyB Jan 31 '20 at 22:00
  • Nobody in their right mind would model heat flow in a regular shape (even two dimensional where the heat source is homogenous with the material) using formulas and that type of sim is massively and exponentially smaller in comparison to an antenna in a box. – Andy aka Jan 31 '20 at 22:22
  • @Andyaka with all due respect using words like "nobody in their right mind" shows you just want to criticism me. In this case if you do not want to help then just stop commenting. – JoeyB Jan 31 '20 at 22:30
  • I see everyone is fixated with doing this in simulations. Then how about one of the commentors show me in the answer section below how to do only 2 iterations mathematically. – JoeyB Jan 31 '20 at 22:37
  • How long is the antenna? Assuming it is on the scale of the length of the container, you would have to incorporate near field considerations. If you want to make exact predictions then you would need to use maxwell's equations and define the boundary conditions of your container. There is likely not a closed for solution to this, which is why approximations are so often used. For example if the observation is outside of the far field region you can approximate the radiation as a TEM wave. – Ben Watson Feb 01 '20 at 05:35

1 Answers1

0

Since any PCB FR-4 materiel will cause EM field inaccuracies from losses, and any bits of copper will case reflection/reradiation, any realworld model will be in error.

For fun, read up on the maths behind the stealth fighter "metal facets" thinking. A Russian wrote the paper.

analogsystemsrf
  • 33,703
  • 2
  • 18
  • 46