Thanks. I am not primarily interested in antenna's per se I but I mean physically small ~cm length wires with oscillating currents near each other. I am interested in the fields and forces especially with retardation effects.When you say "small", do you mean electriclly small, as in way less than half a wavelength? And why are you asking about forces -- is this more than an antenna array pattern problem?
How near each other? What frequencies? Sounds like interacting oscillating electrical dipoles? Can you say what the application is, or would you rather not? Do you have access to any of the COMSOL simulation suite?
Since the purpose is to study this I don't have all the exact answers up front but I would say, current carrying wires, not antenna's or dipoles with on the order of 1 to a few amps of current. Total power ~10-100 Watts. Mass of wires ~grams. Magnetic field strength ~##10^{-5}T## to ##10^{-4}T##. Why is mass important?Current carrying wires or antennas or dipoles? It makes a difference. What range of EM field strengths versus the mass of the wires/antennas or the mass & dipole moments?
The more information you can give, the better the responses we can try to provide you.
Sorry, I guess I really do not understand what your point is. Please elaborate. Thanks.Lordy. I have no idea where you are going with this. So you have 100W of AC RF power magically coupled into a 1cm of wire and you are asking what forces will be induced on another 1cm piece of wire a few cm away? And this is a schoolwork-type question (even for self-study)?
It sounds to me like you are making a current balance from a parallel wire transmission line where the distance between the lines is great when measured in wavelengths.I am interested in the fields and forces especially with retardation effects.
How do you magically couple 100W of TX power into your 1cm TX antenna?Sorry, I guess I really do not understand what your point is. Please elaborate. Thanks.
That's not what I mean. I have two circuits where the wires of each come close at some point for some distance to measure the interaction between them. Each wire has an oscillating current. They interact. I want to simulate that.How do you magically couple 100W of TX power into your 1cm TX antenna?
Where the distance is ~ wavelengths.It sounds to me like you are making a current balance from a parallel wire transmission line where the distance between the lines is great when measured in wavelengths.
I'll have to check that out, thanks.A similar concept would be to simulate or measure the physical forces between the parallel dipole elements of a Yagi antenna.
The finite speed of light. Retarded potentials.What do you mean by "retardation effects" ?
Are the RF currents on the conducting elements traveling or standing waves.The finite speed of light. Retarded potentials.
I want the currents to rise and fall with little variation over the length of the short wire segment if possible. That may imply a standing wave with longer wavelength than the wire segment.Are the RF currents on the conducting elements traveling or standing waves.
Standing waves will have static current nulls and will need to be tuned to the elements. I don't think that is what you want.I want the currents to rise and fall with little variation over the length of the short wire segment if possible.
I just want two current carrying wires with a set phase relationship to each other. It can be a standing wave as long as the current produces a magnetic field that propagates out of the wire like a plain single conductor wire does.Standing waves will have static current nulls and will need to be tuned to the elements. I don't think that is what you want.
I'm not seeking research grants for this. I just want to run a few simulations to see if this concept works at all. Any thoughts regarding free software recommendations?Travelling waves will not have current nodes, but traveling waves will need somewhere to go, such as a dummy load or a long lossy line. The traveling wave is probably easier to model numerically, but harder to fund experimentally due to power consumption.
It would probably have to be around 1 GHZ. I'm looking to model and understand the physical forces of interaction of the lines, cables, wires, whatever and their phases. Similar to the standard example of two current carrying wires but at high frequency. I am asking for simulation software recommendations hopefully available for free. I am not a microwave design expert, I just want to explore an idea I have had which I mentioned in post #5 above and see it it works at all in simulation.You did not mention the frequency range. Might you be looking for mutual induction at power frequency rather than a RF antenna?
You are mixing too many interactions into one model. If the forces do not result in physical movement, then you could solve for all complex currents, using an antenna modelling code such as NEC. Then post process to compute the magnetic fields using FEM, and compute the forces on the conductor currents in the magnetic field.I am asking for simulation software recommendations hopefully available for free.
I don't have a model yet. I want to develop one. Your suggestion is helpful as a process to my goal. Thanks.You are mixing too many interactions into one model. If the forces do not result in physical movement, then you could solve for all complex currents, using an antenna modelling code such as NEC. Then post process to compute the magnetic fields using FEM, and compute the forces on the conductor currents in the magnetic field.
I can do that too. Thanks.It might be easier to make a very simple model and do some vector calculus.
I thought I did explain the purpose of the study in post #5.For some reason you will not explain why you want to investigate this.
Searching for an impossible goal will finally increase the complexity of the solution beyond the capacity of the reasoning brain. Something must give, you turn to simulation.
Of course that all could be true but all I did was ask for suggestions of free EM simulation software so I don't see the need to make any assumptions beyond that.There is usually a good reason why a particular configuration or interaction is not employed, or is difficult to simulate. I suspect you have made a false assumption, or missed a critical step in the analysis. Simulation will not compensate for analysis.
I thought I did explain the purpose of the study in post #5.
That is all too complex for one brain. It seems you are expecting both wires to motor themselves in the same direction which, as a closed system, defies the laws of physics as much as does pulling yourself up by your bootlaces.The two currents will be a quarter period out of phase and the distance will be I believe a half wavelength such that the field and current interaction is in sync on both wires. ie. the forces end up in the same direction.
The Mentors have been dicsussuing this thread for a while now.Are you designing an anti-gravity levitator ?